Modulation of Activity of Proneurotrophins

ABSTRACT

The present invention provides agents for inhibiting binding of a pro-neurotrophin to a Vps10p-domain receptor, in particular the binding of a pro-NGF or a pro-BDNF to a Sortilin receptor. The invention thus provides agents for the manufacture of a medicament, for treating and/or preventing disease or disorders such as but not limited to neurological, neuropsychiatric and ocular diseases, disorders, and degeneration as well as obesity, diabetes, pain and/or nociception in an individual.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Non-Provisional patent application Ser. No. 14/262,398, filed Apr. 25, 2014 (pending), which is a divisional of U.S. Non-Provisional patent application Ser. No. 12/448,422, filed Mar. 29, 2010, which issued as U.S. Pat. No. 8,748,384 on Jun. 10, 2014, which is a §371 U.S. National Stage application of PCT International Application No. PCT/DK2007/000567, filed Dec. 21, 2007 (expired), which claims the benefit of priority under 35 U.S.C. §119(e) of U.S. Provisional Application No. 60/880,771, filed Jan. 16, 2007 (expired), and which claims the benefit of priority under 35 U.S.C. §119(a-d) of Danish Application No. PA200601692, filed Dec. 21, 2006. Each of these applications is hereby incorporated by reference in its entirety. All patent and non-patent references cited in such applications, or in the present application, are also hereby incorporated by reference in their entirety.

REFERENCE TO SEQUENCE LISTING

This application includes one or more Sequence Listings pursuant to 37 C.F.R. 1.821 et seq., which are disclosed in both paper and computer-readable media, and which paper and computer-readable disclosures are herein incorporated by reference in their entireties.

FIELD OF INVENTION

The present invention relates to compositions which are useful in inhibiting pro-neurotrophin activity, as well as methods for the preparation and use thereof. Methods are also provided for screening for agents for use in said compositions.

BACKGROUND OF INVENTION The Neurotrophin Family

Neurotrophins are dimeric peptide hormones. The first member of the neurotrophin family to be discovered was nerve growth factor (NGF), which plays an important role in processes such as the development of sensory and sympathetic neurons of the peripheral nervous system (Levi-Montalcini, R. and Angeleeti, P. U, Physiol. Rev. 48, 534-569 (1968)). The next member of the neurotrophin family to be isolated was brain-derived neurotrophic factor (BDNF), also referred to as neurotrophin-2 (NT-2), the sequence of which was published by Leibrock, J. et al. in 1989 (Nature 341, 149-152). In 1990 several groups identified a neurotrophic factor originally called neuronal factor (NF), now referred to as neurotrophin-3 (NT-3) (Emfors et al., Proc. Nati: Acad. Sci. USA 87, 5454-5458 (1990); Hohn et al., Nature 344, 339; Maisonpierre et al., Science 247, 1446; Rosenthal et al., Neuron 4, 767; Jones and Reichardt, Proc. Natl. Acad. Sci. USA 87, 8060-8064; Kaisho et al., FEBS Lett. 266, 187). Neurotrophins-4 and -5 were then added to the family (Neuron 6, 845-858 (1991); Berkmeier, L. R. et al., Neuron 7, 857-866 (1991); Ip et al., Proc. Natl. Acad. Sci. USA 89, 3060-3064 (1992)). The effects of neurotrophins depend upon their levels of availability, their affinity of binding to transmembrane receptors and the downstream signalling cascades that are stimulated after receptor activation.

Receptors for the Neurotrophin Family

In a similar way to other polypeptide growth factors, neurotrophins affect their target cells through interactions with cell surface receptors. According to current knowledge, neurotrophins bind to two discrete receptor types which can be distinguished pharmacologically: the Trk and p75^(NTR) neurotrophin receptors. p75^(NTR) is a member of the Fas/tumour necrosis factor (TNF) receptor family, and can interact with all the mammalian members of the neurotrophin family with equal affinities (Rodriguez-Tebar et al. 1990, Neuron 4:487-492; Barker and Murphy, 1992, Mol. Cell. Biochem. 100:1-15). Cells expressing TrkA, a tyrosine kinase receptor originally identified as a human oncogene (Mltin-Zanca et al, Nature 319:743-748) bind solely to NGF and exhibit significantly slower dissociation kinetics (Jing et al. 1992, Neurol. 9:1067-1079; Loeb and Greene, 1993, Neuroscience 13:2919-2929). BDNF binds the TrkB receptor only, but NT-3 can bind all three Trk (A, B and C) receptors, with a preference for TrkC. NT-4/5 can bind both TrkA and TrkB (Ip et al. PNAS 89:3060-3064; Klein et al. Neuron 9:947-956). NT-7 does not interact with TrkB or TrkC but can however induce tyrosine phosphorylation of TrkA, indicating a similar receptor specificity as NGF (Nilsson et al., FEBS Lett (1998) Mar. 13; 424(3):285-90). Recombinant purified NT-6 also has a spectrum of actions similar to NGF but with a lower potency (Gotz et al., Nature (1994) Nov. 17; 372(6503):266-9).

The Neurotrophin Family: Precursor Proteins

The biology of the neurotrophin family is complex: the neurotrophins are synthesised intracellularly as 30-35 kDa precursor proteins, containing a signal peptide a prodomain and glycosylation sites. During processing precursor proteins are also cleaved at a dibasic cleavage site by the calcium-dependent serine protease furin and other members of the prohormone convertase family, within the Golgi apparatus. The 12-14 kDa C-terminal product of this cleavage is the mature, biologically active neurotrophin (Seidah et al, Biochem. J. (1996) 314:951-960).

Clinically Relevant Roles of the Neurotrophin Family

Neurotrophins are of clinical interest as they play an important role in neuronal cell survival and differentiation (Thoenen 1991, Trends Neurosci. 14: 165-170; Raffioni et al. 1991, Ann. Rev. Biochem. 62:823-850; Chao, 1992, Neuron 9:583-593; Barbacid 1993, Oncogene 8:2033-2042). Trk receptors transmit signals promoting neuronal survival, whereas p75^(NTR) can induce neuronal apoptosis as well as neuronal survival depending on co-expression of Trk (Miller at al., Cell. Mol. Life Sci. 58:1045-1053 (2001)). Certainly, it has been demonstrated that activation of TrkA receptors can negate the proapoptotic effect of p75^(NTR) in some but not all tissues (Yoon et al., J. Neurosci. (1998) 18:3273-3281; Volosin et al., J. Neurosci. (2006) 26:7756-7766).

It has been demonstrated that the propeptides of neurotrophins play important biological roles: at least three neurotrophin precursor proteins, proNGF, proBDNF and proNT-3 and their proteolytically processed and mature counterpart, NGF, BDNF, NT-3 products differentially activate pro- and anti-apoptotic cellular responses through preferential activation of p75^(NTR) and Trk receptors, respectively—pro-NGF having enhanced affinity for p75^(NTR) receptors and a reduced affinity for Trk receptors relative to the mature forms of NGF. Indeed, it has been demonstrated that pro-NGF induces p75^(NTR)-dependent apoptosis in cultured neurons with minimal activation of TrkA-mediated differentiation or survival (Lee et al., Science (2001), 294:1945-1948).

Furthermore, neurotrophins are of clinical interest as it is known that both up-regulation of neurotrophins and increased p75^(NTR) expression occur under pathological and inflammatory conditions, especially after nerve injury and damage to the vascular system. Indeed, Soilu-Hanninen et al. have demonstrated that the proapoptotic functions of p75^(NTR) are directly implicated in injury-induced apoptosis (Soilu-Hanninen et al., J. Neurosci. 19:4824-4838 (1999)). Recently, it was also demonstrated that proNGF induces p75 mediated death of oligodendrocytes and corticospinal neurons following spinal cord injury (Beatty et al., Neuron (2002), vol. 36, pp. 375-386; Giehl et al, Proc. Natl. Acad. Sci USA (2004), vol. 101, pp 6226-30) and death of basal forebrain neurons in response to kainic acid-induced seizures (Volosin et al, J. Neuroscience (2006), vol. 26, pp 7756-7766).

It has been hypothesized that an imbalance between the precursor and mature form of neurotrophic factors is responsible for the degeneration of selective neuronal populations as it occurs in Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis, and that application of corresponding neurotrophic factor might prevent neuronal degeneration [Appel, S. H., “A unifying hypothesis for the cause of amyotrophic lateral sclerosis, parkinsonism, and Alzheimer's disease,” Ann. Neurol. 10:499-505 (1981), Cunello C and Bruno M. A., Neurochem. Res. (2007) 32:1041-45].

Another reason for interest in targeting neurotrophin pathways for therapy is that studies have provided supporting evidence for the involvement of neurotrophins in depression and antidepressant action (Duman et al. Arch Gen Psychiatry (1997) 54:597-606); for instance infusion of BDNF into the hippocampus has produced an antidepressant effect in two behavioural models of depression (Shirayama et al. (2002), J Neurosci 22(8): 3251-3261). Moreover, a single nucleotide polymorphism in the bdnf gene leading to a valine (Val) to methionine (Met) substitution at codon 66 in the prodomain (BDNF_(Met)) was found to be associated with increased susceptibility in humans heterozygous for the polymorphism to neuropsychiatric disorders including Alzheimer's disease, Parkinson's disease, depression, and bipolar disorder (Chen et al, J. Neuroscience (2005), vol. 25:6156-6166; Kuipers and Bramham Curr. Opin. Drug Discov. Devel. (2006) 9(5):580-6; Bath and Lee, Cogn. Affect. Behay. Neurosci (2006) 1:79-85). In addition, humans heterozygous for BDNF_(Met) were shown to have memory impairments (Egan et al, Cell (2003) 1 vol. 112, pp 257-269).

The Vps10p-Domain Receptor Family

Sortilin (or NTR-3 or GP95), (SEQ ID NO. 1) is a type 1 membrane receptor expressed in a number of tissues, including the brain, spinal cord, testis and skeletal muscle (Petersen et al., J. Biol. Chem., 272:3599-3605 (1997); Herman-Borgmeyer et al., Mol. Brain Res., 65:216-219 (1999)). Sortilin belongs to a family of receptors comprising Sortilin, SorLA (Jacobsen et al., J. Biol. Chem., 271:31379-31383 (1996)), SorCS1, SorCS2 and SorCS3. All the receptors in this family share the structural feature of an approximately 600-amino acid N-terminal domain with a strong resemblance to each of the two domains which constitute the luminal portion of the yeast sorting receptor Vps10p (Marcusson, E. G., et al., Cell, 77:579-586 (1994)). The Vps10p-domain includes a C-terminal segment containing 10 conserved cysteines and an N-terminal propeptide of 40-80 amino acids.

In Sortilin, the propeptide exhibits high affinity binding to the fully processed receptor. Prevention of propeptide cleavage essentially inhibits ligand binding to Sortilin, indicating that the propeptide sterically hinders ligands from gaining access to their binding sites on the receptor (Petersen et al., EMBO J., 18:595-604, 1999).

Some progress has been made as to an understanding of the role of this family: there is evidence suggesting that Sortilin at least contains YXXφ and dileucine motifs, conforming to potent signals for Golgi-endosome sorting (Nielsen et al., EMBO 20(9):2180-2190). It is probable that the other members of the family may also fulfil a similar “sorting” function, not least because they all exhibit homology to Vps10p, the sorting receptor for carboxypeptidase Y (CPY) in yeast. Only a small proportion of Sortilin receptors are present on the cell surface (Mazella et al. J. Biol. Chem. (1998) 273, 26273-26276; Morris et al. J. Biol. Chem. (1998) 273:3582-3587), although expression on the surface membrane can be upregulated by stimuli including insulin in 3T3-L1 adipocytes (Morris et al. J. Biol. Chem. (1998) 273:3582-3587) and neurotensin in embryonic neurons (Chabry et al., J. Biol. Chem. (1993), 286:17138-17144).

Inhibiting Proneurotrophin Activity: The Current State of the Art

Certainly, current understanding of the biological roles of neurotrophins makes the neurotrophin family an attractive target for therapeutic intervention, and some methods for modulation of neurotrophin activity are known:

Mehar M et al., Eur. J. Neruosci. (2006) 24:1575-1580 and Massa S. M. et al, J. Neurosci. (2006), 26:5288-5300 describe how p75 can be used as a drug target to interfere with death-induction following ligand (e.g. proNGF) binding to p75.

WO 2004/056385 discloses general methods for inhibiting binding between Vps10-p domain receptors and neurotrophins/pro-neurotrophins but fails to teach the specific binding site.

SUMMARY OF INVENTION

The present inventors have now identified the binding site on the Sortilin receptor for pro-neurotrophins.

The present invention provides at least one agent capable of inhibiting binding of a pro-neurotrophin to a binding site of a Sortilin receptor, wherein said pro-neurotrophin binds to a binding site on Sortilin comprising an amino acid sequence being at least 70% identical to SEQ ID NO. 25, and wherein said agent either binds to said binding site, or comprises an amino acid sequence being at least 70% identical to SEQ ID NO. 25 or a fragment thereof, in the manufacture of a medicament, for treating and/or preventing and/or ameliorating neurological, neuropsychiatric, and/or ocular diseases, disorders and degeneration, obesity, diabetes, pain and/or nociception in an animal.

In a further aspect, the present invention the at least one agent binds to an amino acid sequence having at least 70% sequence identity to SEQ ID NO. 26 and/or SEQ ID NO. 27 and/or SEQ ID NO. 28, thereby inhibiting binding of a pro-neurotrophin to a Sortilin receptor.

In a further aspect, the at least one agent binds to an amino acid sequence having at least 70% sequence identity to the pro-domain of a pro-neurotrophin, thereby inhibiting binding of said pro-neurotrophin to a Sortilin receptor

In yet another aspect the present invention provides at least one agent capable of inhibiting binding of a pro-neurotrophin to a Sortilin receptor, said at least one agent having at least 90% sequence identity to any of SEQ ID NO. 14, SEQ ID NO. 15, SEQ ID NO. 16, SEQ ID NO. 17, SEQ ID NO. 18, SEQ ID NO. 19, SEQ ID NO. 24, SEQ ID NO. 30, SEQ ID NO. 31, SEQ ID NO. 32, SEQ ID NO. 33, SEQ ID NO. 34, SEQ ID NO. 35, SEQ ID NO. 36, SEQ ID NO. 37, SEQ ID NO. 38, SEQ ID NO. 39, SEQ ID NO. 40, SEQ ID NO. 41 and SEQ ID NO. 42, in the manufacture of a medicament, for treating and/or preventing and/or ameliorating neurological, neuropsychiatric, and/or ocular diseases, disorders and degeneration, obesity, diabetes, pain and/or nociception in an animal.

In another aspect the agents of the present invention are capable of inhibiting the activity of one or more proneurotrophins in an animal and methods for treatment of a disease or disorder in an individual by inhibition of neurotrophin activity. Accordingly, in one aspect the present invention relates to a method for inhibiting the activity of at least one pro-neurotrophin in an animal comprising administering to said animal a sufficient amount of an agent capable of

-   -   (i) binding to a receptor of the Vps10p-domain receptor family         and/or     -   (ii) interfering with binding between a receptor of the         Vps10p-domain receptor family and a proneurotrophin and/or     -   (iii) decreasing the expression of a receptor of the         Vps10p-domain receptor family

In a further aspect agents of the present invention provides agents preventing physical interaction between p75^(NTR) and Sortilin.

Another aspect of the present invention relates to a method or use of at least one agent capable of decreasing the activity of Vps10p-domain receptors in the manufacture of a medicament for treating and/or preventing and/or ameliorating neurological, neuropsychiatric and/or ocular diseases, disorders, degeneration, obesity, diabetes, pain and/or nociception in an animal.

Methods for screening for agents capable of modulating proneurotrophin activity and agents selected using these screening methods are also disclosed, as are methods for determining the effect of an agent on one or more proneurotrophins in cells. The present invention also pertains to methods for modulating the transport of one or more proneurotrophins.

Pharmaceutical compositions comprising the agents of the invention and their use for preventing, treating and/or ameliorating proneurotrophin related diseases are also disclosed.

DETAILED DESCRIPTION OF THE INVENTION Definitions

The term inhibiting as used herein refers to the prevention of binding between two or more components. In the present invention agents capable of inhibiting binding between a Vps10p-domain receptor and a pro-neurotrophin are provided.

The term “binding” as used herein refers to the transient or longer lasting attraction or binding of two or more moieties to one another, mediated by physical forces such as e.g. electrostatic interactions, hydrophobic interactions, dipole-dipole interactions and hydrogen bonds. The term “hydrophobic interaction” as used herein refers to any interaction occurring between essentially non-polar (hydrophobic) components located within attraction range of one another in a polar environment (e.g. water). As used herein, attraction range is on the scale of about 100 nm. A particular type of hydrophobic interaction is exerted by “Van der Waal's forces”, i.e. the attractive forces between non-polar molecules that are accounted for by quantum mechanics. Van der Waal's forces are generally associated with momentary dipole moments which are induced by neighbouring molecules and which involve changes in electron distribution. The term “hydrogen bond” as used herein refers to an attractive force, or bridge, which may occur between a hydrogen atom which is bonded covalently to an electronegative atom, for example, oxygen, sulphur, or nitrogen, and another electronegative atom. The hydrogen bond may occur between a hydrogen atom in a first molecule and an electronegative atom in a second molecule (intermolecular hydrogen bonding). Also, the hydrogen bond may occur between a hydrogen atom and an electronegative atom which are both contained in a single molecule (intramolecular hydrogen bonding). The term “electrostatic interaction” as used herein refers to any interaction occurring between charged components, molecules or ions, due to attractive forces when components of opposite electric charge are attracted to each other. Examples include, but are not limited to: ionic interactions, covalent interactions, interactions between a ion and a dipole (ion and polar molecule), interactions between two dipoles (partial charges of polar molecules), hydrogen bonds and London dispersion bonds (induced dipoles of polarizable molecules). Thus, for example, “ionic interaction” or “electrostatic interaction” refers to the attraction between a first, positively charged molecule and a second, negatively charged molecule. Ionic or electrostatic interactions include, for example, the attraction between a negatively charged bioactive agent (input examples relevant to this invention). The term “dipole-dipole interaction” as used herein refers to the attraction which can occur among two or more polar molecules. Thus, “dipole-dipole interaction” refers to the attraction of the uncharged, partial positive end of a first polar molecule to the uncharged, partial negative end of a second polar molecule. “Dipole-dipole interaction” also refers to intermolecular hydrogen bonding.

Functional equivalents and variants of polynucleotides encoding a proneurotrophin activity modulator and polypeptides comprising such a proneurotrophin activity modulator: “functional equivalents” and “variants” are used interchangeably herein. In one preferred embodiment of the invention there is also provided variants of proneurotrophin activity modulator and variants of fragments thereof. When being polypeptides, variants are determined on the basis of their degree of identity or their homology with a predetermined amino acid sequence, said predetermined amino acid sequence being one of SEQ ID NO: proneurotrophin activity modulator, or, when the variant is a fragment, a fragment of any of the aforementioned amino acid sequences, respectively.

The term inhibiting binding between a proneurotrophin and a Sortilin receptor as used herein refer to a method of providing an agent capable of preventing the binding of a proneurotrophin to a Sortilin receptor and in particular binding to a part of the Sortilin receptor comprising any of the SEQ ID NO. 25 to 28 or any fragment or variant thereof or binding of said agent to said proneurotrophin, thus preventing binding of said pro-neurotrophin to SEQ ID NO. 25, SEQ ID NO. 26, SEQ ID NO. 27 or SEQ ID NO. 28 or any fragment or variant thereof.

Accordingly, variants preferably have at least 70% sequence identity, for example at least 72% sequence identity, for example at least 75% sequence identity, for example at least 80% sequence identity, such as at least 85% sequence identity, for example at least 90% sequence identity, such as at least 91% sequence identity, for example at least 91% sequence identity, such as at least 92% sequence identity, for example at least 93% sequence identity, such as at least 94% sequence identity, for example at least 95% sequence identity, such as at least 96% sequence identity, for example at least 97% sequence identity, such as at least 98% sequence identity, for example 99% sequence identity with any of the predetermined sequences.

Sequence identity is determined in one embodiment by utilising fragments of proneurotrophin activity modulator peptides comprising at least 25 contiguous amino acids and having an amino acid sequence which is at least 80%, such as 85%, for example 90%, such as 95%, for example 99% identical to the amino acid sequence of any of SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 25, SEQ ID NO: 26, SEQ ID NO: 27 AND SEQ ID NO: 28 respectively, wherein the percent identity is determined with the algorithm GAP, BESTFIT, or FASTA in the Wisconsin Genetics Software Package Release 7.0, using default gap weights.

The following terms are used to describe the sequence relationships between two or more polynucleotides: “predetermined sequence”, “comparison window”, “sequence identity”, “percentage of sequence identity”, and “substantial identity”.

A “predetermined sequence” is a defined sequence used as a basis for a sequence comparison; a predetermined sequence may be a subset of a larger sequence, for example, as a segment of a full-length DNA or gene sequence given in a sequence listing, such as a polynucleotide sequence of SEQ ID NO:1, or may comprise a complete DNA or gene sequence. Generally, a predetermined sequence is at least 20 nucleotides in length, frequently at least 25 nucleotides in length, and often at least 50 nucleotides in length.

Since two polynucleotides may each (1) comprise a sequence (i.e., a portion of the complete polynucleotide sequence) that is similar between the two polynucleotides, and (2) may further comprise a sequence that is divergent between the two polynucleotides, sequence comparisons between two (or more) polynucleotides are typically performed by comparing sequences of the two polynucleotides over a “comparison window” to identify and compare local regions of sequence similarity. A “comparison window”, as used herein, refers to a conceptual segment of at least 20 contiguous nucleotide positions wherein a polynucleotide sequence may be compared to a predetermined sequence of at least 20 contiguous nucleotides and wherein the portion of the polynucleotide sequence in the comparison window may comprise additions or deletions (i.e., gaps) of 20 percent or less as compared to the predetermined sequence (which does not comprise additions or deletions) for optimal alignment of the two sequences.

Optimal alignment of sequences for aligning a comparison window may be conducted by the local homology algorithm of Smith and Waterman (1981) Adv. Appl. Math. 2: 482, by the homology alignment algorithm of Needleman and Wunsch (1970) J. Mol. Biol. 48: 443, by the search for similarity method of Pearson and Lipman (1988) Proc. Natl. Acad. Sci. (U.S.A.) 85: 2444, by computerized implementations of these algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin Genetics Software Package Release 7.0, Genetics Computer Group, 575 Science Dr., Madison, Wis.), or by inspection, and the best alignment (i.e., resulting in the highest percentage of homology over the comparison window) generated by the various methods is selected.

The term “sequence identity” means that two polynucleotide sequences are identical (i.e., on a nucleotide-by-nucleotide basis) over the window of comparison. The term “percentage of sequence identity” is calculated by comparing two optimally aligned sequences over the window of comparison, determining the number of positions at which the identical nucleic acid base (e.g., A, T, C, G, U, or I) occurs in both sequences to yield the number of matched positions, dividing the number of matched positions by the total number of positions in the window of comparison (i.e., the window size), and multiplying the result by 100 to yield the percentage of sequence identity. The terms “substantial identity” as used herein denotes a characteristic of a polynucleotide sequence, wherein the polynucleotide comprises a sequence that has at least 85 percent sequence identity, preferably at least 90 to 95 percent sequence identity, more usually at least 99 percent sequence identity as compared to a predetermined sequence over a comparison window of at least 20 nucleotide positions, frequently over a window of at least 25-50 nucleotides, wherein the percentage of sequence identity is calculated by comparing the predetermined sequence to the polynucleotide sequence which may include deletions or additions which total 20 percent or less of the predetermined sequence over the window of comparison. The predetermined sequence may be a subset of a larger sequence, for example, as a segment of the full-length SEQ ID NO:1 polynucleotide sequence illustrated herein.

As applied to polypeptides, a degree of identity of amino acid sequences is a function of the number of identical amino acids at positions shared by the amino acid sequences. A degree of homology or similarity of amino acid sequences is a function of the number of amino acids, i.e. structurally related, at positions shared by the amino acid sequences.

An “unrelated” or “non-homologous” sequence shares less than 40% identity, though preferably less than 25% identity, with one of the proneurotrophin activity modulator polypeptide sequences of the present invention. The term “substantial identity” means that two peptide sequences, when optimally aligned, such as by the programs GAP or BESTFIT using default gap weights, share at least 80 percent sequence identity, preferably at least 90 percent sequence identity, more preferably at least 95 percent sequence identity or more (e.g., 99 percent sequence identity). Preferably, residue positions which are not identical differ by conservative amino acid substitutions.

Conservative amino acid substitutions refer to the interchangeability of residues having similar side chains. For example, a group of amino acids having aliphatic side chains is glycine, alanine, valine, leucine, and isoleucine; a group of amino acids having aliphatic-hydroxyl side chains is serine and threonine, a group of amino acids having amide-containing side chains is asparagine and glutamine; a group of amino acids having aromatic side chains is phenylalanine, tyrosine, and tryptophan; a group of amino acids having basic side chains is lysine, arginine, and histidine; and a group of amino acids having sulphur-containing side chains is cysteine and methionine. Preferred conservative amino acids substitution groups are: valine-leucineisoleucine, phenylalanine-tyrosine, lysine-arginine, alanine-valine, and asparagineglutamine.

Additionally, variants are also determined based on a predetermined number of conservative amino acid substitutions as defined herein below. Conservative amino acid substitution as used herein relates to the substitution of one amino acid (within a predetermined group of amino acids) for another amino acid (within the same group), wherein the amino acids exhibit similar or substantially similar characteristics.

Within the meaning of the term “conservative amino acid substitution” as applied herein, one amino acid may be substituted for another within the groups of amino acids indicated herein below:

-   i) Amino acids having polar side chains (Asp, Glu, Lys, Arg, His,     Asn, Gln, Ser, Thr, Tyr, and Cys,) -   ii) Amino acids having non-polar side chains (Gly, Ala, Val, Leu,     Ile, Phe, Trp, Pro, and Met) -   iii) Amino acids having aliphatic side chains (Gly, Ala Val, Leu,     Ile) -   iv) Amino acids having cyclic side chains (Phe, Tyr, Trp, His, Pro) -   v) Amino acids having aromatic side chains (Phe, Tyr, Trp) -   vi) Amino acids having acidic side chains (Asp, Glu) -   vii) Amino acids having basic side chains (Lys, Arg, His) -   viii) Amino acids having amide side chains (Asn, Gln) -   ix) Amino acids having hydroxy side chains (Ser, Thr) -   x) Amino acids having sulphur-containing side chains (Cys, Met), -   xi) Neutral, weakly hydrophobic amino acids (Pro, Ala, Gly, Ser,     Thr) -   xii) Hydrophilic, acidic amino acids (Gln, Asn, Glu, Asp), and -   xiii) Hydrophobic amino acids (Leu, Ile, Val)

Accordingly, a variant or a fragment thereof according to the invention may comprise, within the same variant of the sequence or fragments thereof, or among different variants of the sequence or fragments thereof, at least one substitution, such as a plurality of substitutions introduced independently of one another.

It is clear from the above outline that the same variant or fragment thereof may comprise more than one conservative amino acid substitution from more than one group of conservative amino acids as defined herein above.

The addition or deletion of at least one amino acid may be an addition or deletion of from preferably 2 to 250 amino acids, such as from 10 to 20 amino acids, for example from 20 to 30 amino acids, such as from 40 to 50 amino acids. However, additions or deletions of more than 50 amino acids, such as additions from 50 to 100 amino acids, addition of 100 to 150 amino acids, addition of 150-250 amino acids, are also comprised within the present invention. The deletion and/or the addition may—independently of one another—be a deletion and/or an addition within a sequence and/or at the end of a sequence.

The polypeptide fragments according to the present invention, including any functional equivalents thereof, may in one embodiment comprise less than 250 amino acid residues, such as less than 240 amino acid residues, for example less than 225 amino acid residues, such as less than 200 amino acid residues, for example less than 180 amino acid residues, such as less than 160 amino acid residues, for example less than 150 amino acid residues, such as less than 140 amino acid residues, for example less than 130 amino acid residues, such as less than 120 amino acid residues, for example less than 110 amino acid residues, such as less than 100 amino acid residues, for example less than 90 amino acid residues, such as less than 85 amino acid residues, for example less than 80 amino acid residues, such as less than 75 amino acid residues, for example less than 70 amino acid residues, such as less than 65 amino acid residues, for example less than 60 amino acid residues, such as less than 55 amino acid residues, for example less than 50 amino acid residues.

“Functional equivalency” as used in the present invention is, according to one preferred embodiment, established by means of reference to the corresponding functionality of a predetermined fragment of the sequence.

Functional equivalents or variants of a proneurotrophin activity modulator will be understood to exhibit amino acid sequences gradually differing from the preferred predetermined proneurotrophin activity modulator sequence, as the number and scope of insertions, deletions and substitutions including conservative substitutions increase. This difference is measured as a reduction in homology between the preferred predetermined sequence and the fragment or functional equivalent.

All fragments or functional equivalents of SEQ ID NO: proneurotrophin activity modulator are included within the scope of this invention, regardless of the degree of homology that they show to the respective, predetermined proneurotrophin activity modulator sequences disclosed herein. The reason for this is that some regions of the proneurotrophin activity modulator are most likely readily mutatable, or capable of being completely deleted, without any significant effect on the binding activity of the resulting fragment.

A functional variant obtained by substitution may well exhibit some form or degree of native proneurotrophin activity modulator activity, and yet be less homologous, if residues containing functionally similar amino acid side chains are substituted. Functionally similar in this respect refers to dominant characteristics of the side chains such as hydrophobic, basic, neutral or acidic, or the presence or absence of steric bulk. Accordingly, in one embodiment of the invention, the degree of identity is not a principal measure of a fragment being a variant or functional equivalent of a preferred predetermined fragment according to the present invention.

The homology between amino acid sequences may be calculated using well known scoring matrices such as any one of BLOSUM 30, BLOSUM 40, BLOSUM 45, BLOSUM 50, BLOSUM 55, BLOSUM 60, BLOSUM 62, BLOSUM 65, BLOSUM 70, BLOSUM 75, BLOSUM 80, BLOSUM 85, and BLOSUM 90.

Fragments sharing homology with fragments of SEQ ID NO:1 to 42, respectively, are to be considered as falling within the scope of the present invention when they are preferably at least about 90 percent homologous, for example at least 92 percent homologous, such as at least 94 percent homologous, for example at least 95 percent homologous, such as at least 96 percent homologous, for example at least 97 percent homologous, such as at least 98 percent homologous, for example at least 99 percent homologous with said predetermined fragment sequences, respectively. According to one embodiment of the invention, the homology percentages refer to identity percentages.

Additional factors that may be taken into consideration when determining functional equivalence according to the meaning used herein are i) the ability of antisera to detect a proneurotrophin activity modulator fragment according to the present invention, or ii) the ability of the functionally equivalent proneurotrophin activity modulator fragment to compete with the corresponding proneurotrophin activity modulator in an assay. One method of determining a sequence of immunogenically active amino acids within a known amino acid sequence has been described by Geysen in U.S. Pat. No. 5,595,915 and is incorporated herein by reference.

A further suitably adaptable method for determining structure and function relationships of peptide fragments is described in U.S. Pat. No. 6,013,478, which is herein incorporated by reference. Also, methods of assaying the binding of an amino acid sequence to a receptor moiety are known to the skilled artisan.

In addition to conservative substitutions introduced into any position of a preferred predetermined proneurotrophin activity modulator, or a fragment thereof, it may also be desirable to introduce non-conservative substitutions in any one or more positions of such a proneurotrophin activity modulator.

A non-conservative substitution leading to the formation of a functionally equivalent fragment of proneurotrophin activity modulator would for example i) differ substantially in polarity, for example a residue with a non-polar side chain (Ala, Leu, Pro, Trp, Val, Ile, Leu, Phe or Met) substituted for a residue with a polar side chain such as Gly, Ser, Thr, Cys, Tyr, Asn, or Gin or a charged amino acid such as Asp, Glu, Arg, or Lys, or substituting a charged or a polar residue for a non-polar one; and/or ii) differ substantially in its effect on polypeptide backbone orientation such as substitution of or for Pro or Gly by another residue; and/or iii) differ substantially in electric charge, for example substitution of a negatively charged residue such as Glu or Asp for a positively charged residue such as Lys, His or Arg (and vice versa); and/or iv) differ substantially in steric bulk, for example substitution of a bulky residue such as His, Trp, Phe or Tyr for one having a minor side chain, e.g. Ala, Gly or Ser (and vice versa).

Variants obtained by substitution of amino acids may in one preferred embodiment be made based upon the hydrophobicity and hydrophilicity values and the relative similarity of the amino acid side-chain substituents, including charge, size, and the like. Exemplary amino acid substitutions which take various of the foregoing characteristics into consideration are well known to those of skill in the art and include: arginine and lysine; glutamate and aspartate; serine and threonine; glutamine and asparagine; and valine, leucine and isoleucine.

In addition to the variants described herein, sterically similar variants may be formulated to mimic the key portions of the variant structure and that such compounds may also be used in the same manner as the variants of the invention. This may be achieved by techniques of modelling and chemical designing known to those of skill in the art. It will be understood that all such sterically similar constructs fall within the scope of the present invention.

In a further embodiment the present invention relates to functional variants comprising substituted amino acids having hydrophilic values or hydropathic indices that are within +/−4.9, for example within +/−4.7, such as within +/−4.5, for example within +/−4.3, such as within +/−4.1, for example within +/−3.9, such as within +/−3.7, for example within +/−3.5, such as within +/−3.3, for example within +/−3.1, such as within +/−2.9, for example within +/−2.7, such as within +/−2.5, for example within +/−2.3, such as within +/−2.1, for example within +/−2.0, such as within +/−1.8, for example within +/−1.6, such as within +/−1.5, for example within +/−1.4, such as within +/−1.3 for example within +/−1.2, such as within +/−1.1, for example within +/−1.0, such as within +/−0.9, for example within +/−0.8, such as within +/−0.7, for example within +/−0.6, such as within +/−0.5, for example within +/−0.4, such as within +/−0.3, for example within +/−0.25, such as within +/−0.2 of the value of the amino acid it has substituted.

The importance of the hydrophilic and hydropathic amino acid indices in conferring interactive biologic function on a protein is well understood in the art (Kyte & Doolittle, 1982 and Hopp, U.S. Pat. No. 4,554,101, each incorporated herein by reference).

The amino acid hydropathic index values as used herein are: isoleucine (+4.5); valine (+4.2); leucine (+3.8); phenylalanine (+2.8); cysteine/cystine (+2.5); methionine (+1.9); alanine (+1.8); glycine (−0.4); threonine (−0.7); serine (−0.8); tryptophan (−0.9); tyrosine (−1.3); proline (−1.6); histidine (−3.2); glutamate (−3.5); glutamine (−3.5); aspartate (−3.5); asparagine (−3.5); lysine (−3.9); and arginine (−4.5) (Kyte & Doolittle, 1982).

The amino acid hydrophilicity values are: arginine (+3.0); lysine (+3.0); aspartate (+3.0.+−0.1); glutamate (+3.0.+−0.1); serine (+0.3); asparagine (+0.2); glutamine (+0.2); glycine (0); threonine (−0.4); proline (−0.5.+−0.1); alanine (−0.5); histidine (−0.5); cysteine (−1.0); methionine (−1.3); valine (−1.5); leucine (−1.8); isoleucine (−1.8); tyrosine (−2.3); phenylalanine (−2.5); tryptophan (−3.4) (U.S. Pat. No. 4,554,101).

In addition to the peptidyl compounds described herein, sterically similar compounds may be formulated to mimic the key portions of the peptide structure and that such compounds may also be used in the same manner as the peptides of the invention. This may be achieved by techniques of modelling and chemical designing known to those of skill in the art. For example, esterification and other alkylations may be employed to modify the amino terminus of, e.g., a di-arginine peptide backbone, to mimic a tetra peptide structure. It will be understood that all such sterically similar constructs fall within the scope of the present invention.

Peptides with N-terminal alkylations and C-terminal esterifications are also encompassed within the present invention. Functional equivalents also comprise glycosylated and covalent or aggregative conjugates formed with the same or other proneurotrophin activity modulator fragments and/or proneurotrophin activity modulator molecules, including dimers or unrelated chemical moieties. Such functional equivalents are prepared by linkage of functionalities to groups which are found in fragment including at any one or both of the N- and C-termini, by means known in the art.

Functional equivalents may thus comprise fragments conjugated to aliphatic or acyl esters or amides of the carboxyl terminus, alkylamines or residues containing carboxyl side chains, e.g., conjugates to alkylamines at aspartic acid residues; O-acyl derivatives of hydroxyl group-containing residues and N-acyl derivatives of the amino terminal amino acid or amino-group containing residues, e.g. conjugates with fMet-Leu-Phe or immunogenic proteins. Derivatives of the acyl groups are selected from the group of alkyl-moieties (including C3 to C10 normal alkyl), thereby forming alkanoyl species, and carbocyclic or heterocyclic compounds, thereby forming aroyl species. The reactive groups preferably are difunctional compounds known per se for use in cross-linking proteins to insoluble matrices through reactive side groups.

Covalent or aggregative functional equivalents and derivatives thereof are useful as reagents in immunoassays or for affinity purification procedures. For example, a fragment of proneurotrophin activity modulator according to the present invention may be insolubilized by covalent bonding to cyanogen bromide-activated Sepharose by methods known per se or adsorbed to polyolefin surfaces, either with or without glutaraldehyde cross-linking, for use in an assay or purification of anti-neurotrophin activity modulator antibodies or cell surface receptors. Fragments may also be labelled with a detectable group, e.g., radioiodinated by the chloramine T procedure, covalently bound to rare earth chelates or conjugated to another fluorescent moiety for use in e.g. diagnostic assays.

Mutagenesis of a preferred predetermined fragment of proneurotrophin activity modulator can be conducted by making amino acid insertions, usually on the order of about from 1 to 10 amino acid residues, preferably from about 1 to 5 amino acid residues, or deletions of from about from 1 to 10 residues, such as from about 2 to 5 residues.

In one embodiment the fragment of proneurotrophin activity modulator is synthesised by automated synthesis. Any of the commercially available solid-phase techniques may be employed, such as the Merrifield solid phase synthesis method, in which amino acids are sequentially added to a growing amino acid chain (see Merrifield, J. Am. Chem. Soc. 85:2149-2146, 1963).

Equipment for automated synthesis of polypeptides is commercially available from suppliers such as Applied Biosystems, Inc. of Foster City, Calif., and may generally be operated according to the manufacturer's instructions. Solid phase synthesis will enable the incorporation of desirable amino acid substitutions into any fragment of proneurotrophin activity modulator according to the present invention. It will be understood that substitutions, deletions, insertions or any subcombination thereof may be combined to arrive at a final sequence of a functional equivalent. Insertions shall be understood to include amino-terminal and/or carboxyl-terminal fusions, e.g. with a hydrophobic or immunogenic protein or a carrier such as any polypeptide or scaffold structure capable as serving as a carrier.

Oligomers including dimers including homodimers and heterodimers of fragments of proneurotrophin activity modulator according to the invention are also provided and fall under the scope of the invention. Proneurotrophin activity modulator functional equivalents and variants can be produced as homodimers or heterodimers with other amino acid sequences or with native proneurotrophin activity modulator sequences. Heterodimers include dimers containing immunoreactive proneurotrophin activity modulator fragments as well as proneurotrophin activity modulator fragments that need not have or exert any biological activity.

Neurotrophin activity modulator fragments according to the invention may be synthesised both in vitro and in vivo. Method for in vitro synthesis are well known, and methods being suitable or suitably adaptable to the synthesis in vivo of proneurotrophin activity modulator are also described in the prior art. When synthesized in vivo, a heist cell is transformed with vectors containing DNA encoding proneurotrophin activity modulator or a fragment thereof. A vector is defined as a replicable nucleic acid construct. Vectors are used to mediate expression of proneurotrophin activity modulator. An expression vector is a replicable DNA construct in which a nucleic acid sequence encoding the predetermined proneurotrophin activity modulator fragment, or any functional equivalent thereof that can be expressed in vivo, is operably linked to suitable control sequences capable of effecting the expression of the fragment or equivalent in a suitable host. Such control sequences are well known in the art.

Cultures of cells derived from multicellular organisms represent preferred host cells. In principle, any higher eukaryotic cell culture is workable, whether from vertebrate or invertebrate culture. Examples of useful host cell lines are VERO and HeLa cells, Chinese hamster ovary (CHO) cell lines, and WI38, BHK, COS-7, 293 and MDCK cell lines. Preferred host cells are eukaryotic cells known to synthesize endogenous proneurotrophin activity modulator. Cultures of such host cells may be isolated and used as a source of the fragment, or used in therapeutic methods of treatment, including therapeutic methods aimed at promoting or inhibiting a growth state, or diagnostic methods carried out on the human or animal body.

Pharmaceutical agent: the terms “pharmaceutical agent” or “drug” or “medicament” refer to any therapeutic or prophylactic agent which may be used in the treatment (including the prevention, diagnosis, alleviation, or cure) of a malady, affliction, condition, disease or injury in a patient. Therapeutically useful genetic determinants, peptides, polypeptides and polynucleotides may be included within the meaning of the term pharmaceutical or drug. As defined herein, a “therapeutic agent,” “pharmaceutical agent” or “drug” or “medicament” is a type of bioactive agent.

The term “bioactive agent” as used herein refers to any a substance which may be used in connection with an application that is therapeutic or diagnostic, such as, for example, in methods for diagnosing the presence or absence of a disease in a patient and/or methods for the treatment of a disease in a patient. “Bioactive agent” refers to substances, which are capable of exerting a biological effect in vitro and/or in vivo. The bioactive agents may be neutral, positively or negatively charged. Suitable bioactive agents include, for example, prodrugs, diagnostic agents, therapeutic agents, pharmaceutical agents, drugs, oxygen delivery agents, blood substitutes, synthetic organic molecules, polypeptides, peptides, vitamins, steroids, steroid analogues and genetic determinants, including nucleosides, nucleotides and polynucleotides.

Treatment: the term “treatment” as used herein refers to a method involving therapy including surgery of a clinical condition in an individual including a human or animal body. The therapy may be ameliorating, curative or prophylactic, i.e. reducing the risk of acquiring a disease.

antisense-RNA: an RNA molecule capable of causing gene silencing by specifically binding to an mRNA molecule of interest. antisense-DNA: a DNA molecule capable of causing gene silencing by specifically binding to an mRNA molecule of interest. siRNA: “small interfering RNA” (siRNA) is a short (often, but not restricted to, less than 30 nucleotides long) double-stranded RNA molecule capable of causing genespecific silencing in mammalian cells

Gene “silencing”: a process leading to reduced expression of endogenous genes. Gene silencing is preferably the result of post-transcriptional reduction of gene expression.

Up-regulation of expression: a process leading to increased expression of genes, preferably of endogenous genes.

In vitro/in vivo: the terms are used in their normal meaning.

Polypeptide: The term “polypeptide” as used herein refers to a molecule comprising at least two amino acids. The amino acids may be natural or synthetic. “Oligopeptides” are defined herein as being polypeptides of length not more than 100 amino acids. The term “polypeptide” is also intended to include proteins, i.e. functional biomolecules comprising at least one polypeptide; when comprising at least two polypeptides, these may form complexes, be covalently linked or may be non-covalently linked. The polypeptides in a protein can be glycosylated and/or lipidated and/or comprise prosthetic groups.

“Polynucleotide” as used herein refers to a molecule comprising at least two nucleic acids. The nucleic acids may be naturally occurring or modified, such as locked nucleic acids (LNA), or peptide nucleic acids (PNA). Polynucleotide as used herein generally pertains to

-   -   i) a polynucleotide comprising a predetermined coding sequence,         or     -   ii) a polynucleotide encoding a predetermined amino acid         sequence, or     -   iii) a polynucleotide encoding a fragment of a polypeptide         encoded by polynucleotides (i) or (ii), wherein said fragment         has at least one predetermined activity as specified herein; and     -   iv) a polynucleotide the complementary strand of which         hybridizes under stringent conditions with a polynucleotide as         defined in any one of (i), (ii) and (iii), and encodes a         polypeptide, or a fragment thereof, having at least one         predetermined activity as specified herein; and     -   v) a polynucleotide comprising a nucleotide sequence which is         degenerate to the nucleotide sequence of polynucleotides (iii)         or (iv);     -   or the complementary strand of such a polynucleotide.

A “purified antibody” is an antibody at least 60 weight percent of which is free from the polypeptides and naturally-occurring organic molecules with which it is naturally associated. Preferably, the preparation comprises antibody in an amount of at least 75 weight percent, more preferably at least 90 weight percent, and most preferably at least 99 weight percent.

DETAILED DESCRIPTION

The present inventors have identified that proneurotrophins bind to the Sortilin receptor of the Vps10p-domain receptor family which results in apoptosis when a ternery complex is formed by the co-binding of p75^(NTR).

Accordingly, the present invention relates to modulation of the activity of at least one proneurotrophin.

Without being bound by theory it is believed that Vps10p-domain receptor family is involved in one or more of the following mechanisms in relation to proneurotrophins:

-   -   Retrograde transport, including uptake of proneurotrophin and         p75^(NTR)     -   Transport within biosynthetic pathways, including sorting of         proneurotrophin and transport from the Golgi network     -   Release of proneurotrophins     -   Signalling, including modulation of cellular transport and         signalling by formation of ternary complexes with p75 and         pro-neurotrophin

Thus, one aspect of the present invention is a method for modulating the activity of at least one pro-neurotrophin in a single cell or an organism, including an animal, comprising administering to said animal a sufficient amount of an agent capable of binding to a receptor of the Vps10p-domain receptor family or capable of interfering with binding between a receptor of the Vps10p-domain receptor family and a proneurotrophin.

Receptors of the Vps10p-Domain Receptor Family

The term “receptor of the Vps10p family” refers to a family of receptors characterised by having an N-terminal Vps10p domain; said Vpsp10p domain family comprises SorLA, Sortilin, SorCS1, SorCS2, or SorCS3, see FIG. 1. In one embodiment of the present invention, any of the receptors of the Vps10p domain family may be used; more preferably, the receptor comprises the Vps10p domain, the 10 CC module, a transmembrane segment as well as a cytoplasmic segment mediating cellular sorting and internalization as well as mediating binding to cytoplasmic adaptors affecting cellular signalling. In particular the receptor used is Sortilin.

Neurotrophins/Pro-Neurotrophins

The term “neurotrophin” as used herein refers to any member of the neurotrophin family, said neurotrophin family comprising nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5). In one embodiment of the present invention, any member of the neurotrophin family may be used; however, it is preferred that the neurotrophin is NGF or BDNF.

The term “pro-neurotrophin” as used herein may refer to any pro-neurotrophin family comprising a prodomain operatively linked to the corresponding mature neurotrophin, said family of pro-neurotrophins comprising pro-NGF, pro-BDNF, pro-NT-3 and pro-NT-4/5. In one embodiment of the present invention, any proneurotrophin may be used, however it is preferred that the pro-neurotrophin is pro-NGF or pro-BDNF.

Inhibition of Proneurotrophin Activity

The terms “proneurotrophin-mediated” activity, “activity of a proneurotrophin” or “proneurotrophin activity” refer to a biological activity that is normally promoted, either directly or indirectly, in the presence of a proneurotrophin or neurotrophin. Pro-neurotrophin activities include, but are not restricted to differentially activating both pro- and anti-apoptotic cellular responses, through preferential activation of p75^(NTR) or TrkA receptors respectively. It has been hypothesized that the lack of neurotrophic factors is responsible for the degeneration of selective neuronal populations as it occurs in Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis.

In preferred embodiments of the present invention, one ore more of these activities of proneurotrophin(s) are inhibited directly or indirectly by the administration of an agent to an animal.

The terms inhibition or inhibited refer to any decrease in the biological activity of a bioactive agent, for example a proneurotrophin. In one embodiment of the present invention, such an inhibition refer to a decrease in the binding of a proneurotrophin to a Vps10p-domain receptor, especially the binding of a pro-NGF or a pro-BDNF to a Sortilin receptor. The efficiency of inhibiting effect of agents of the present invention may be measured by competitive inhibitory experiments using BIAcore (surface plasmon resonance).

Agents Capable of Inhibiting Binding of a Proneurotrophin to a Vps10p-Domain Receptor

In one preferred embodiment of the present invention, an agent is administered to the animal, said agent being capable of inhibiting the binding between a receptor of the Vps10p-domain receptor family and a proneurotrophin.

In another, equally preferred embodiment, the agent is capable of binding to a receptor of the Vps10p-domain receptor family and/or pro-neurotrophin thereby interfering with the activity of a proneurotrophin, either directly or indirectly.

The agent capable of exhibiting one or more of the above mentioned effects may be any type of agent, for example the agent may be selected from the group comprising proteins, peptides, polypeptides or organic molecules, In a preferred embodiment the agent is an antibody, a compound or a polypeptide, and the agent is most preferably a polypeptide or an organic molecule. Said agents may bind to either of the following sequences:

Sortilin: RIFRSSDFAKNF (Residues 120-131 of SEQ ID NO: 1) SorLA: YLWITFDFCNTL (Residues 105-116 of SEQ ID NO: 2) SorCS1: SLLISSDEGATY (Residues 254-265 of SEQ ID NO: 3) SorCS2: SLFLSADEGATF (Residues 1-12 of SEQ ID NO: 44) SorCS3: SILISSDEGATY (Residues 277-288 of SEQ ID NO: 5)

The abovementioned sequences are all subsequences of SEQ ID NO: 1 to 5 respectively. The invention inhibits binding of a pro-neurotrophin to the sequences above thus preventing the pro-neurotrophin:Vps10p-domain receptor binary complex from performing a biologically or physiologically relevant activity. Thus the agents of the present invention may be used to prevent diseases and disorders as specified herein below.

In a particularly preferred embodiment of the present invention, the agent administered to the animal is capable of inhibiting the binding of a proneurotrophin to a sortilin receptor thus inhibiting the receptor activity, said activity may be, but is not restricted to, one or more of the following:

-   -   i) cellular sorting of the receptor     -   ii) receptor binding directly or indirectly by ligand bridging         to other receptors, such as the p75 and Trk receptors     -   iii) sortilin receptor signalling

In one embodiment of the present invention, the agent is capable of inhibiting binding of a proneurotrophin to a receptor of the Vps10p-domain receptor family. Such inhibition may for example be due to binding of the agent either to the proneurotrophin and/or the Vps10p-domain receptor such as the receptor Sortilin.

In one embodiment the agent is a fragment or a variant of the Vps10p-domain of the Sortilin receptor said fragment or variant capable of binding the pro-domain of a pro-neurotrophin or a fragment or a variant thereof. In particular the agent include but is not limited to the fragments FAKNFV (SEQ ID NO:25, residues 14-20), RIFR (SEQ ID NO:59) and RIFRSSDF (SEQ ID NO:60) as displayed in FIG. 17 describing the length analysis of pro-domain-BDNF binding to sortilin peptides. Any fragment or variant capable of binding to a pro-neurotrophin is included herein. In particular a fragment is a peptide comprising a sequence corresponding to any of SEQ ID NOs: 25 to 28. This domain is herein referred to as the pro-neurotrophin binding motif of the Vps10p domain. Peptides comprising the SEQ ID NOs: 25 to 28 may be at least 3 residues long, such as 5 residues long, such as 7 residues long, such as 10 residues long, such as 13 residues long, such as 15 residues long, such as 20 residues long, such as 25 residues long, such as 30 residues long, such as 35 residues long, such as 40 residues long, such as 50 residues long, such as 60 residues long, such as 70 residues long, such as 80 residues long, such as at least 90 residues long, such as 100 residues long, such as 125 residues long such as 150 residues long, such as 175 residues long such as 200 residues long. The sequences within such a peptide identical to SEQ ID NO:25 may lie in the beginning of said peptide, the end, the middle or anywhere in between. Said peptides may furthermore be variants of the original SEQ ID NO:1 sequence, variants as defined in the above. Preferably the variant comprise conservative amino acid substitutions or other, benign alterations to the original sequence. A preferred peptide according to the present invention comprises SEQ ID NO: 26 and fragments and variants hereof, such as the sequences identified in SEQ ID NO: 27 and/or SEQ ID NO: 28 and fragments and variant of these. Examples of variants are also given in FIGS. 15 and 16, in which a sequence falling within SEQ ID NO: 25 is the subject of a substitution analysis. Herein it is confirmed that the especially relevant parts of the present binding motif of the Vps10p domain falls within the sequence described in SEQ ID NO: 26, and the most essential parts hereof again are the sequences identified in SEQ ID NO: 27 and SEQ ID NO: 28. Regarding either of SEQ ID NO: 1, 25, 26, 27 or 28, FIGS. 15 and 16 indicates that e.g. R196 as counted using pre-pro-Sortilin (corresponds to R163 for proSortilin) may in a manner conserving the, ability to bind BDNF be substituted with either F, G, H, I, L, N, P, Q, T, V, W or Y, and preferably is substituted with either F, H, I, L, V, W or Y. Likewise any of the other residues of SEQ ID NO: 1, 25, 26, 27 or 28 may be substituted. I197 as counted using pre-pro-Sortilin (corresponds to I164 for proSortilin) is thus preferably substituted with A, F, G, H, P, R, S, T, V or Y; F198 as counted using pre-pro-Sortilin (corresponds to F165 for proSortilin) is preferably substituted with I, L, R, or W; R199 as counted using pre-pro-Sortilin (corresponds to R166 for proSortilin) is preferably substituted with A, D, F, G, H, I, L, S, T, V, W or Y; F203 as counted using pre-pro-Sortilin (corresponds to F170 for proSortilin) is preferably substituted with L, P or R; A204 as counted using pre-pro-Sortilin (corresponds to A171 for proSortilin) is preferably substituted with D, E, G, H, I, K, L, M, N, P, Q, R, S, T, V, W or Y; K205 as counted using pre-pro-Sortilin (corresponds to K172 for proSortilin) is preferably substituted with A, F, G, H, I, L, M, N, P, Q, R, S, T, V, W or Y; N206 as counted using pre-pro-Sortilin (corresponds to N173 for proSortilin) is preferably substituted with A, F, G, H, I, K, L, M, P, Q, R, S, T, or V; and F207 as counted using pre-pro-Sortilin (corresponds to F174 for proSortilin) is preferably substituted with H, I, K, L, N, P, Q, R, or V. Any of these substitutions may be made alone or in combination with any of the other preferred substitutions or any of the other methods of generating variants as mentioned herein.

In another embodiment the agent is capable of binding to the receptor. The agent may bind to any part of the receptor relevant for inhibiting the binding of the neurotrophin. Accordingly, the agent may be capable of inhibiting the binding of said neurotrophin or said pro-neurotrophin to a receptor of the Vps10p-domain receptor family by binding to an intracellular part of the receptor.

An object of the invention is to provide agents that alone or assisted by a pharmaceutical agent/formulation are capable of crossing the blood/brain barrier.

An example of an agent according to the invention is an antibody directed against an extra-cellular part of the receptor. In an even more preferred embodiment, the antibody is purified. In the preferred embodiment wherein the agent is an antibody directed against an extra-cellular part of the receptor, the antibody is preferably directed against a peptide comprising a sequence corresponding to the binding motif of the Vps10p domain, said motif comprising SEQ ID NO: 25, 26, 27 or 28 or a fragment or variant hereof. Said fragment may comprise between 3 and 31 amino residues, such as between 3 and 29 amino acid residues, for example between 3 and 27 amino acid residues, such as between 3 and 25 amino acid residues, for example between 3 and 23 amino acid residues, such as between 3 and 21 amino acid residues, for example between 3 and 19 amino acid residues, such as between 3 and 17 amino acid residues, for example between 3 and 15 amino acid residues, such as between 3 and 13 amino acid residues, for example between 3 and 11 amino acid residues, such as between 3 and 9 amino acid residues, for example between 3 and 7 amino acid residues, such as between 3 and 5 amino acid residues, for example 4 amino acid residues, such as between 5 and 31 amino acid residues, for example between 7 and 31 amino acid residues, such as between 9 and 31 amino acid residues, for example between 11 and 31 amino acid residues, such as between 13 and 31 amino acid residues, for example between 15 and 31 amino acid residues, such as between 17 and 31 amino acid residues, for example between 19 and 31 amino acid residues, such as between 21 and 31 amino acid residues, for example between 23 and 31 amino acid residues, such as between 25 and 31 amino acid residues, for example between 27 and 31 amino acid residues, such as between 29 and 31 amino acid residues, for example 30 amino acid residues.

In particular the antibody should be directed against a position in this motif so that the antibody sterically blocks the binding of the pro-neurotrophin to the receptor.

In yet another embodiment, compounds of the present invention, thus capable of acting as inhibitors of proneurotrophins to Vps10p domain receptors, comprises polypeptides of between 1 and 500 amino acid residues comprising one or more of of the SEQ ID NO:s 25, 26, 27 and 28.

In yet another embodiment the agent is a neurotensin analog and/or a neurotensin system modulator including, but not limited to SEQ ID NO. 24 and SEQ ID NOs.29 to 42. Neurotensin and the neurotensin system modulators bind to Vps10-p domain receptors for example the Sortilin receptor or fragments thereof such as and not limited to the sequences displayed in FIG. 17, thus preventing any normal and/or natural ligand from binding to Sortilin hence acting as antagonists to the neurotrophins that otherwise would interact with Sortilin and herein disclosed fragments thereof. Furthermore, said neurotensin and neurotensin system modulators may bind to an alternate binding site of the Sortilin receptor inducing conformational changes affecting the binding affinity between neurotrophins and Sortilin in an antagonistic manner. Said neurotensin and neurotensin system modulators are preferably capable of crossing the blood-brain barrier and of the Vps10p-domain receptors preferably bind to Sortilin. In yet a preferred embodiment, neurotensin and the neurotensin system modulators do not have any significant binding affinity towards or adverse effects upon bind to other Vps10p-domain receptors or indeed other receptors than Sortilin.

Vps10p-domain receptors, especially Sortilin, initially identified as neurotensin receptor 3 (NTR-3) have partial overlapping substrate specificity with neurotensin receptors 1 and 2 (NTR-1 and NTR-2) both which bind NT(1-13) with high affinity. In addition a number of neurotensin system modulators are known ligands of NTR-1 and NTR-2. Examples hereof are the peptides NT66L (SEQ ID NO. 15), NT67L (SEQ ID NO. 16), NT69L (SEQ ID NO. 17), Eisai (SEQ ID NO. 18), JMV-449 (SEQ ID NO. 19), PD-149163 (SEQ ID NO. 20), PD-149598 (SEQ ID NO. 21), PD-156425 of the structure:

and PD-156556 (SEQ ID NO. 23), CGX-1160 (SEQ ID NO. 24), PD-147113 (SEQ ID NO 29), GZR-123 (SEQ ID NO 30), NT64D (SEQ ID NO. 31), NT64L (SEQ ID NO. 32), NT65L (SEQ ID NO. 33), NT66D (SEQ ID NO. 34), NT69L′ (SEQ ID NO. 35), NT71 (SEQ ID NO. 36), NT72 (SEQ ID NO. 37), NT73 (SEQ ID NO. 38), NT74 (SEQ ID NO. 39), NT75 (SEQ ID NO. 40), NT76 (SEQ ID NO. 41), NT77 (SEQ ID NO. 42) and the compounds SR-142948A, SR-48692, UK-73093 and L-737631. All of these compounds and peptides are agents according to the present invention. Furthermore, derivates of the above compounds and variant or fragments or peptides comprising the abovementioned peptides are agents according to the present invention. By derivates are understood compounds retaining a substantial and/or significant part of the structure of the mentioned compounds but substituted differently, i.e. comprising other substituents. Derivates may also be molecules that are capable of interacting in the same manner as the parent compound, i.e. interact with the same residues on the Vps10p-domain receptor. Examples of such substituents comprise and are not limited to: Alicyclic groups: the term “alicyclic group” means a cyclic hydrocarbon group having properties resembling those of aliphatic groups. Aliphatic groups: in the context of the present invention, the term “aliphatic group” means a saturated or unsaturated linear or branched hydrocarbon group. This term is used to encompass alkyl, alkenyl, and alkynyl groups, for example. Alkyl groups: the term “alkyl group” means a saturated linear or branched hydrocarbon group including, for example, methyl, ethyl, isopropyl, t-butyl, heptyl, dodecyl, octadecyl, amyl, 2-ethylhexyl, and the like. Alkenyl groups: the term “alkenyl group” means an unsaturated, linear or branched hydrocarbon group with one or more carbon-carbon double bonds, such as a vinyl group. Alkynyl groups: the term “alkynyl group” means an unsaturated, linear or branched hydrocarbon group with one or more carbon-carbon triple bonds; Amphiphils: substance containing both polar, water-soluble and nonpolar, water-insoluble groups. Aromatic group: the term “aromatic group” or “aryl group” means a mono- or poly-cyclic aromatic hydrocarbon group. Cyclic groups: the term “cyclic group” means a closed ring hydrocarbon group that is classified as an alicyclic group, aromatic group, or heterocyclic group. Cycloalkenyls: means a monovalent unsaturated carbocyclic radical consisting of one, two or three rings, of three to eight carbons per ring, which can optionally be substituted with one or two substituents selected from the group consisting of hydroxy, cyano, lower alkenyl, lower alkoxy, lower haloalkoxy, alkenylthio, halo, haloalkenyl, hydroxyalkenyl, nitro, alkoxycarbonenyl, amino, alkenylamino, alkenylsulfonyl, arylsulfonyl, alkenylaminosulfonyl, arylaminosulfonyl, alkylsulfonylamino, arylsulfonylamino, alkenylaminocarbonyl, arylaminocarbonyl, alkenylcarbonylamino and arylcarbonylamino. Cycloalkyls: meaning a monovalent saturated carbocyclic radical consisting of one, two or three rings, of three to eight carbons per ring, which can optionally be substituted with one or two substituents selected from the group consisting of hydroxy, cyano, lower alkyl, lower alkoxy, lower haloalkoxy, alkylthio, halo, haloalkyl, hydroxyalkyl, nitro, alkoxycarbonyl, amino, alkylamino, alkylsulfonyl, arylsulfonyl, alkylaminosulfonyl, arylaminosulfonyl, alkylsulfonylamino, arylsulfonylamino, alkylaminocarbonyl, arylaminocarbonyl, alkylcarbonylamino and arylcarbonylamino.

Cationic groups: A chemical group capable of functioning as a proton donor when a compound comprising the chemical group is dissolved in a solvent, preferably when dissolved in water. Generally a “Group”/Moiety/substitute is well understood in this technical area, and a large degree of substitution is not only tolerated, but is often advisable. Substitution is anticipated on the materials of the present invention. As a means of simplifying the discussion and recitation of certain terminology used throughout this application, the terms “group” and “moiety” are used to differentiate between chemical species that allow for substitution or that may be substituted and those that do not allow or may not be so substituted. Thus, when the term “group” is used to describe a chemical substituent, the described chemical material includes the unsubstituted group and that group with O, N, or S atoms, for example, in the chain as well as carbonyl groups or other conventional substitution. Where the term “moiety” is used to de-scribe a chemical compound or substituent, only an unsubstituted chemical material is intended to be included. For example, the phrase “alkyl group” is intended to include not only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like, but also alkyl substituents bearing further substituents known in the art, such as hydroxy, alkoxy, alkylsulfonyl, halogen atoms, cyano, nitro, amino, carboxyl, etc. Thus, “alkyl group” includes ether groups, haloal-kyls, nitroalkyls, carboxyalkyls, hydroxyalkyls, sulfoalkyls, etc. On the other hand, the phrase “alkyl moiety” is limited to the inclusion of only pure open chain saturated hydrocarbon alkyl substituents, such as methyl, ethyl, propyl, t-butyl, and the like. The same definitions apply to “alkenyl group” and “alkenyl moiety”; to “alkynyl group” and “alkynyl moiety”; to “cyclic group” and “cyclic moiety; to “alicyclic group” and “alicyclic moiety”; to “aromatic group” or “aryl group” and to “aromatic moiety” or “aryl moiety”; as well as to “heterocyclic group” and “heterocyclic moiety”. Heterocyclic group: the term “heterocyclic group” means a closed ring hydrocarbon in which one or more of the atoms in the ring is an element other than carbon (e.g., nitrogen, oxygen, sulphur, etc.). Heterocyclyl means a monovalent saturated cyclic radical, consisting of one to two rings, of three to eight atoms per ring, incorporating one or two ring heteroatoms (chosen from N, O or S(O)0-2, and which can optionally be substituted with one or two substituents selected from the group consisting of hydroxyl, oxo, cyano, lower alkyl, lower alkoxy, lower haloalkoxy, alkylthio, halo, haloalkyl, hydroxyalkyl, nitro, alkoxycarbonyl, amino, alkylamino, alkylsulfonyl, arylsulfonyl, alkylaminosulfonyl, arylaminosulfonyl, alkylsulfonylamino, arylsulfonylamino, alkylaminofarbonyl, arylaminocarbonyl, alkylcarbonylamino, or arylcarbonylamino. Heteroaryl means a monovalent aromatic cyclic radical having one to three rings, of four to eight atoms per ring, incorporating one or two heteroatoms (chosen from nitrogen, oxygen, or sulphur) within the ring which can optionally be substituted with one or two substituents selected from the group consisting of hydroxy, cyano, lower alkyl, lower alkoxy, lower haloalkoxy, alkylthio, halo, haloalkyl, hydroxyalkyl, nitro, alkoxycarbonyl, amino, alkylamino, alkylsulfonyl, arylsulfonyl, alkylaminosulfonyl, arylaminosulfonyl, alkylsulfonylamino, arylsulfonylamino, alkylaminocarbonyl, arylaminocarbonyl, alkylcarbonlamino and arylcarbonylamino. Substituted lower alkyl means a lower alkyl having one to three substituents selected from the group consisting of hydroxyl, alkoxy, amino, amido, carboxyl, acyl, halogen, cyano, nitro and thiol. Variants, fragments or peptides comprising the neurotensin system modulator peptides may be generated by conservative amino acid substitution as defined in the above or by the inclusion, and/or substitution of any of the residues for any naturally occurring L-, D- or amino acid or any synthetic amino acid derivative. Furthermore, the bonds between the residues in mentioned amino acids may be altered forming non-amide bond linked amino acid peptides.

Thus in an embodiment of the present invention neurotensin system modulators as defined in any of SEQ ID NOs. 10-11, 13-24, 29-42 and derivates or variants hereof and the compounds SR-142948A, SR-48692, UK-73093 and L-737631 and derivates or variants hereof are agents of the present invention. Furthermore, fragments of the peptides are also agents of the present invention. These fragments may be one or more amino acids shorter than the peptides according to the SEQ ID NO's listed above. It is of importance that the peptides that interact with Sortilin are retained in these fragments. Preferred agents are SR-48692, NT-69L and CGX-1160 and/or variants hereof.

In another preferred embodiment of the present invention, the agent is capable of binding to an intracellular part of the receptor and/or the transmembrane part of a receptor of the Vps10p domain receptor family. In particular the agent may be capable of binding to the cytoplasmic part of the receptor of the Vps10p domain receptor family, such as to a part of Sortilin corresponding to SEQ ID NO: 1 or a fragment thereof comprising any of SEQ ID NOs: 25 to 28.

In particular binding of an agent to the intracellular and transmembrane parts of the receptor may lead to modulation of the proneurotrophin activity through a modulation of the transport of at least one pro-neurotrophin out of, into or within cells expressing the receptor of the Vps10p domain receptor family as discussed below.

In another preferred embodiment, the agent is capable of modulating the expression of a receptor of the Vps10p-domain receptor family and thereby interfering with the activity of at least one proneurotrophin. The modulation may be either inhibition or stimulation of the expression. Preferable methods for modulating the expression of the receptor include, but are not restricted to:

-   -   (i) Blocking or inhibiting the activity of the translation         products of one or more Vps10p-domain receptor genes and/or one         or more derivatives thereof, by inhibiting mRNA translation or         transcriptional activation using antisense nucleic acids.     -   (ii) Inactivating mRNA by ribozymes targeted to the mRNAs         encoding one or more Vps10p-domain receptor genes and/or one or         more derivatives thereof.     -   (iii) Inhibition of the intracellularly present translation         products of the Vps10p-domain receptor genes by administering         molecules which mimic targets of the translation products of one         or more Vps10p-domain receptor genes and/or one or more         derivatives thereof thereby competing with their natural         targets.     -   (iv) Stimulating the expression of one or more Vps10p-domain         receptor genes and/or one or more derivatives thereof, for         example in one preferred embodiment, an agent is administered to         cells in vitro or in vivo. Such an agent may act either         specifically or non-specifically. It is also possible to         activate genes responsible for further growth of differentiated         tissue by introducing one or more Vps10p-domain receptor genes         and/or one or more derivatives thereof into the respective cells         and tissue by means of gene therapy. For this purpose the         respective nucleic acid sequences may be put under control of a         strong promoter, which optionally can be activated and         deactivated upon administration of a stimulus to the         cell/tissue.     -   (v) Stimulating expression of one or more Vps10p-domain receptor         genes and/or one or more derivatives thereof by administering         directly to the respective cell/tissue a translation product,         either a peptide or a protein, that is derived from one or more         Vps10p-domain receptor gene and/or one or more derivative         thereof. Due to the low molecular weight of any of the         aforementioned translation products these peptides/proteins can         easily be applied to the cell, for example using encapsulation         delivery systems.

The change in expression level of the receptor of the Vps10p-domain receptor family may be assayed for using methods known to those skilled in the art, including but not restricted to: DNA arrays or microarrays (Brazma and Vilo, FEBS Lett., 2000, 480, 17-24; Cells, et al., FEBS Lett., 2000, 480, 2-16), SAGE (serial analysis of gene expression)(Madden, et al., Drug Discov. Today, 2000, 5, 415-425), READS (restriction enzyme amplification of digested cDNAs) (Prashar and Weissman, Methods Enzymol., 1999, 303, 258-72), TOGA (total gene expression analysis) (Sutcliffe, et al., Proc. Natl. Acad. Sci. U.S.A, 2000, 97, 1976-81), protein arrays and proteomics (Cells, et al., FEBS Lett., 2000, 480, 2-16; Jungblut, et al., Electrophoresis, 1999, 20, 2100-10), expressed sequence tag (EST) sequencing (Cells, et al., FEBS Lett, 2000, 480, 2-16; Larsson, et al., J. Biotechnol., 2000, 80, 143-57), subtractive RNA fingerprinting (SURF) (Fuchs, et al., Anal. Biochem., 2000, 286, 91-98; Larson, et al., Cytometry, 2000, 41, 203-208), subtractive cloning, differential display (DD) (Jurecic and Belmont, Curr. Opin. Microbiol., 2000, 3, 316-21), comparative genomic hybridization (Carulli, et al., J. Cell Biochem. Suppl., 1998, 31, 286-96), FISH (fluorescent in situ hybridization) techniques (Going and Gusterson, Eur. J. Cancer, 1999, 35, 1895-904) and mass spectrometry methods (reviewed in (To, Comb. Chem. High Throughput Screen, 2000, 3, 235-41).

Methods for Treating a Disease or Disorder

In one preferred embodiment of the present invention, the invention comprises a method for treating a disease or disorder in an individual. Said method comprises administering to said individual, in a pharmaceutically acceptable carrier, a sufficient amount of an agent capable of interfering with binding between a receptor of the Vps10p-domain receptor family and a proneurotrophin. By “sufficient amount” herein is meant a dose that produces the therapeutic effects for which it is administered. The exact dose will depend on the disorder to be treated, and will be ascertainable by one skilled in the art using known techniques. In general, the agent of the present invention is administered to an animal in an amount of from 1 μg/kg to about 100 mg/kg per day. In addition, as is known in the art, adjustments for age as well as the body weight, general health, sex, diet, time of administration, drug interaction and the severity of the disease may be necessary, and will be ascertainable with routine experimentation by those skilled in the art.

Agents of the present invention are believed to be useful in promoting the development, maintenance, or regeneration of neurons in vitro and in vivo, including central (brain and spinal chord), peripheral (sympathetic, parasympathetic, sensory, and enteric neurons), and motor neurons. Accordingly, agents of the present invention may be utilized in methods for the treatment of a variety of neurological diseases, disorders and degeneration. In a preferred embodiment, the formulations of the present invention are administered to a patient to treat neural disorders. By “neural disorders” herein is meant disorders of the central and/or peripheral nervous system that are associated with neuron degeneration or damage. Specific examples of neural disorders include, but are not limited to, Alzheimer's disease, Parkinson's disease, Huntington's chorea, stroke, ALS, peripheral neuropathies, and other conditions characterized by necrosis or loss of neurons, whether central, peripheral, or motor neurons, in addition to treating damaged nerves due to trauma, burns, kidney dysfunction or injury, pancreatic dysfunction or injury, lung dysfunction or injury, injury to fatty tissue, and the toxic effects of chemotherapeutics used to treat cancer and AIDS. For example, peripheral neuropathies associated with certain conditions, such as neuropathies associated with diabetes, AIDS, or chemotherapy may be treated using the formulations of the present invention.

In various embodiments of the invention, agents are administered to patients in whom the nervous system has been damaged by trauma, surgery, stroke, ischemia, infection, metabolic disease, nutritional deficiency, malignancy, or toxic agents, to promote the survival or growth of neurons, or in whatever conditions are treatable with NGF, NT-3, BDNF or NT4-5. For example, agents of the invention can be used to promote the survival or growth of motor neurons that are damaged by trauma or surgery. Also, agents of the invention can be used to treat motor neuron disorders, such as amyotrophic lateral sclerosis (Lou Gehrig's disease), Bell's palsy, and various conditions involving spinal muscular atrophy, or paralysis. Agents of the present invention can be used to treat human neurodegenerative disorders, such as Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, Huntington's chorea, Down's Syndrome, nerve deafness, and Meniere's disease.

Neurotrophins are essential for the health and well-being of the nervous system. For example NGF (nerve growth factor), BDNF (brain-derived neurotrophic factor), NT-3 (neurotrophin-3) and NT-4 (neurotrophin-4) also mediate additional higher-order activities, such as learning, memory and behaviour, in addition to their established functions for cell survival. Agents of the present invention can thus be used as cognitive enhancers, to enhance learning, particularly in patients suffering from dementias or trauma. Alzheimer's disease, which has been identified by the National Institutes of Aging as accounting for more than 50% of dementia in the elderly, is also the fourth or fifth leading cause of death in Americans over 65 years of age. Four million Americans, 40% of Americans over age 85 (the fastest growing segment of the U.S. population), have Alzheimer's disease. Twenty-five percent of all patients with Parkinson's disease also suffer from Alzheimer's disease-like dementia. And in about 15% of patients with dementia, Alzheimer's disease and multi-infarct dementia coexist. The third most common cause of dementia, after Alzheimer's disease and vascular dementia, is cognitive impairment due to organic brain disease related directly to alcoholism, which occurs in about 10% of alcoholics. However, the most consistent abnormality for Alzheimer's disease, as well as for vascular dementia and cognitive impairment due to organic brain disease related to alcoholism, is the degeneration of the cholinergic system arising from the basal forebrain (BF) to both the codex and hippocampus (Bigl et al. in Brain Cholinergic Systems, M. Steriade and D. Biesold, eds., Oxford University Press, Oxford, pp. 364-386 (1990)). And there are a number of other neurotransmitter systems affected by Alzheimer's disease (Davies Med. Res. Rev. 3:221 (1983)). However, cognitive impairment, related for example to degeneration of the cholinergic neurotransmitter system, is not limited to individuals′suffering from dementia. It has also been seen in otherwise healthy aged adults and rats. Studies that compare the degree of learning impairment with the degree of reduced cortical cerebral blood flow in aged rats show a good correlation (Berman et al. Neurobiol. Aging 9:691 (1988)). In chronic alcoholism the resultant organic brain disease, like Alzheimer's disease and normal aging, is also characterized by diffuse reductions in cortical cerebral blood flow in those brain regions where cholinergic neurons arise (basal forebrain) and to which they project (cerebral cortex) (Lofti et al., Cerebrovasc. and Brain Metab. Rev 1:2 (1989)). Such dementias can be treated by administration of agents of the present invention.

It is an object of the present invention to use the agents hereof to treat multiple sclerosis. The agents of the present invention may be used alone or in combination with other medicaments. Examples of such compounds include and are not limited to:

Interferon beta (e.g. beta-1a and/or beta-1b), glatiramer acetate (Copaxone, a mixture of polypeptides which may protect important myelin proteins by substituting itself as the target of immune system attack), mitoxantrone and natalizumab (Tysabri), corticosteroids, and monoclonal antibodies.

In addition, agents of the present invention may be used in the treatment of spinal cord injuries and/or in combination with other treatment applied after spinal cord injuries. Current examples of such agents include and are not limited to the steroid drug methylprednisolone given within the first 8 hours after injury to reduce the damage to nerve cells.

Moreover, agents of the present invention may be used in the treatment of Parkinson's disease (PD) and or in combination with other medicaments given in the treatment of Parkinson's disease; such agents include and are not limited to: levodopa, carbidopa, benserazide, talcopone, entacapone, mucuna pruriens, dopamine agonists such as bromocriptine, pergolide, pramipexole, ropinirole, cabergoline, apomorphine, and lisuride, MAO-B inhibitors such as selegiline and rasagiline. In addition other non-pharmacological treatments such as surgical interventions, speech therapy and physical exercise has proven to be moderately effective and agent of the present invention may be used in combination with these methods of therapy as well. Furthermore, the agents of the present invention may be used in combination with methods employing gene and/or cellular therapy, such as the implantation of cells genetically engineered to produce dopamine or stem cells that transform into dopamine-producing cells or the agents may be used in combination with GDNF (glial-derived neurotrophic factor) infusion. This involves the infusion of GDNF into the basal ganglia using surgically implanted catheters. Also, treatment with neuroprotective agents such as apoptotic drugs (CEP 1347 and CTCT346), lazaroids, bioenergetics and/or antiglutamatergic agents in combination with the agents described herein above fall within the scope of the present invention.

In yet another embodiment, agents of the current invention may be used in the treatment of stroke. Furthermore, agents of the present invention maybe used in combination with medicaments used in the treatment of stroke such as antiplatelet medication (e.g. aspirin, clopidogrel and dipyridamole) or anticoagulant medication such as warfarin or the tissue plasminogen activator, tPA. The method of clearing the blocked blood vessel by mechanical thrombectomy may also be used in combination with agents of the present invention.

Further, agents of the present invention are preferably used to treat neuropathy, and especially peripheral neuropathy. “Peripheral neuropathy” refers to a disorder affecting the peripheral nervous system, most often manifested as one or a combination of motor, sensory, sensorimotor, or autonomic neural dysfunction. The wide variety of morphologies exhibited by peripheral neuropathies can each be attributed uniquely to an equally wide number of causes. For example, peripheral neuropathies can be genetically acquired, can result from a systemic disease, or can be induced by a toxic agent. Examples include, but are not limited to, diabetic peripheral neuropathy, distal sensorimotor neuropathy, or autonomic neuropathies such as reduced motility of the gastrointestinal tract or atony of the urinary bladder. Examples of neuropathies associated with systemic disease include post-polio syndrome or AIDS-associated neuropathy; examples of hereditary neuropathies include Charcot-Marie-Tooth disease, Refsum's disease, Abetalipoproteinemia, Tangier disease, Krabbe's disease, Metachromatic leukodystrophy, Down's Syndrome, Fabry's disease, and Dejerine-Sottas syndrome; and examples of neuropathies caused by a toxic agent include those caused by treatment with a chemotherapeutic agent such as vincristine, cisplatin, methotrexate, or 3′-azido-3′-deoxythymidine.

Furthermore, neuronal degeneration as seen in aging or senescence is an object of the present invention. Senescence is the combination of processes of deterioration which follow the period of development of an organism and is generally characterized by the declining ability to respond to stress, increasing homeostatic imbalance and increased risk of disease. Aging itself is by some gerontologists considered a “disease” that may be curable. In accordance with this view aging is an accumulation of damage to macromolecules, cells, tissues and organs, thus advanced biochemical and molecular repair technologies may be able to counter the damage caused by senescence. Agents of the present invention may be utilized in methods for the protection and or prevention of damage induced by senescence, especially neuronal degeneration due to senescence. In a preferred embodiment, the formulations of the present invention are administered to a patient to treat senescence related neuronal degeneration.

It is within the scope of the present invention to provide agent for the treatment, prevention and/or amelioration of neuropsychiatric disorders. Certain of the below mentioned conditions may also be referred to as neural diseases. Neuropsychiatric diseases and disorder may be divided onto three main groups: thought/psychotic disorders (these make it hard for people to separate what is real from what is not, e.g. schizophrenia), mood disorders (affect how a person feels; for example, very sad or hopeless. If a mood disorder becomes severe, it can appear to be a thought disorder, e.g. bipolar disorder and depressive disorders), anxiety disorders (make a person feel overwhelmingly anxious and fearful, e.g. Panic disorder and obsessive-compulsive disorder (OCD)). Examples of neuropsychiatric disorders include any neuropsychiatric disease or disorder such as, but not limited to: schizophrenia, bipolar disorder, depression, mania, substance dependence and abuse (e.g. alcohol dependence), depression, bipolar disorder, Alzheimer's disease, Parkinson's disease, psychotic disorders, schizophrenia, schizoaffective disorder, anxiety disorders, post-traumatic stress disorder, obsessive-compulsive disorder, borderline personality disorder, schizotypal personality disorder, avoidant personality disorder and antisocial personality disorder. The pathogenesis of schizophrenia may be ascribed to early maldevelopment of brain tissue. Accumulating preclinical and clinical data indicate that dysfunctions of neurotrophins, especially nerve growth factor (NGF), brain derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) may contribute to impaired brain development, neuroplasticity and synaptic “dysconnectivity” leading to the schizophrenic syndrome. Furthermore there are several lines of evidence supporting a role for neurotrophins and proneurotrophins in the treatment of depression, chronic stress and substance abuse. An enhancement in neurotrophic support and associated augmentation in synaptic plasticity and function may form the basis for antidepressant efficacy. Thus neuropsychiatric diseases and disorders such as schizophrenia, depression, chronic stress, and substance abuse are objects of the present invention and may be treated, prevented or ameliorated by administration of the agents herein described.

Other disorders, diseases and degenerative conditions in a mammal that may be treated by a therapeutically effective amount of one or more agents of the present invention are diseases, disorders and degenerations of the eye. The conditions of this type that are of special interest to the present invention may be divided in to four categories: Acquired macular diseases (AMD), Retinal vascular diseases, Retina detachment, and hereditary fundus dystrophies. Preferably, the disorders are Acquired macular diseases such as exodative and non-exodative age-related macular degeneration, Retinal vascular diseases such as diabetic retinoplasy and blood clots in the eye, and hereditary fundus dystrophies such as lebers. Other disorders specifically relate to senescence of the eye that in accordance with most anatomical and physiological processes follow a gradual decline. Agents of the present invention are useful in preventing or improving pathological conditions of the eye.

In addition, pain and nociception are indications of relevance for the agents of the present invention. Pain is, and nociception may be, an unpleasant sensation, ranging in intensity from slight through severe to indescribable. Where pain is a subjective feeling, nociception is a measurable physiological event that may occur without pain being felt. Physiological pain can be classified according to source and its related pain detecting neurons (nociceptors) into cutaneous pain, somatic pain, visceral pain, phantom limb pain and neuropathic pain. Cutaneous pain is caused by injury to the skin or superficial tissues. Somatic pain originates from ligaments, tendons, bones, blood vessels, and even nerves themselves. Visceral pain originates from body's viscera, or organs. Phantom limb pain is the sensation of pain from a limb that has been lost or from which a person no longer receives physical signals. Neuropathic pain, or “neuralgia”, can occur as a result of injury or disease to the nerve tissue itself.

Pain and/or nociceptions may arise due to different causes, a main cause being trauma. Trauma may occur too any body part, and any trauma that causes pain or nociception is within the scope of the present invention. Other examples of pain and nociceptions include but are not limited to: Head and neck related: Jaw—Temporal arteritis (serious); Ear—otitis media (very common esp. in children), otitis externa; Eye—glaucoma; Head—migraine, tension headache, cluster headache, cancer, cerebral aneurysm, sinusitis, meningitis, Neck pain—MI (atypical); Thorax: Back cancer; Breast—perimenstrual, cancer; Chest—MI (common and fatal), GERD (very common), pancreatitis, hiatal hernia, aortic dissection (rare), pulmonary embolism (more frequently asymptomatic), Costochondritis, Shoulder—cholecystitis (right side), MSK; Abdomen: Abdominal—Left and right upper quadrant—peptic ulcer disease, gastroenteritis, hepatitis, pancreatitis, cholecystitis, MI (atypical), abdominal aortic aneurysm, gastric cancer, Left and right lower quadrant—appendicitis (serious), ectopic pregnancy (serious/women only), pelvic inflammatory disease (women only), diverticulitis (common in old), urolithiasis (kidney stone), pyelonephritis, cancer (colorectal cancer most common); Back: Back—MSK (muscle strain), cancer, spinal disc herniation, degenerative disc disease, coccyx (coccydynia); Limbs: Arm—MI (classically left, sometimes bilateral), MSK; Leg—deep vein thrombosis, peripheral vascular disease (claudication), MSK, spinal disc herniation, sciatica; Joints: Classically small joints—osteoarthritis (common in old), rheumatoid arthritis, systemic lupus erythematosis, gout, pseudogout; Classically large joints (hip, knee)—osteoarthritis (common in old), septic arthritis, hemarthrosis; Classically back—ankylosing spondylitis, inflammatory bowel disease; Other—psoriatic arthritis, Reiter's syndrome. Agents of the present invention may be used as analgesics or analgetic agents to treat and/or ameliorate any of the above types of pain and/or nociceptions.

Moreover, obesity is an indication of relevance for the agents of the present invention. Obesity is a condition in which the natural energy reserve, stored in the adipose tissue of humans and other mammals, is increased to a point where it is a risk factor for certain health conditions or increased mortality. Excessive body weight has been shown to predispose to various diseases, particularly cardiovascular diseases, sleep apnea, osteoarthritis and non-insulin-dependent diabetes mellitus. Obesity is the single most frequent contributor of type 2 diabetes. Type 2 diabetes is a metabolic disorder that is caused by insulin resistance and relative insulin deficiency, and chronic hyperglycemia. It is rapidly increasing in the world and it is estimated to increase according to epidemic trends. A Vps10p domain receptor gene has recently been associated with type 2 diabetes in mouse and rat. Other types of diabetes are also within the scope of the present invention, these are diabetes type 1 and gestational diabetes (GDM) occurring during pregnancy and other types. Type 1 is due to autoimmune destruction of the insulin-producing cells. It is an object of the present invention to provide agents for the treatment of obesity, diabetes type 1, 2, GDM and diabetes related disorders.

In addition to diabetes, obesity also enhances the risk of myocardial infarction due to atherosclerosis which is an objective for agents of the present invention.

Accordingly, a method of treating, preventing and/or ameliorating a proneurotrophin related disorder, disease or degeneration in a mammal comprising administering to the mammal a therapeutically effective amount of one or more agents of the present invention is provided. These proneurotrophin related diseases, disorders or degenerative conditions may be any of the conditions of the above such as neuronal disorders, neuronal degeneration, neuropsychiatric disorders and diseases, senescence, pain and nociception, ocular diseases, disorders or degeneration, obesity and obesity related diseases and diabetes. Pain as used herein above refer to peripheral pain. Ocular diseases as used herein refer to retinal diseases, disorders and degeneration of the retina.

It is an object of the present invention that any of the herein described agents may be used alone or in combination with one another. The agents of the present invention may thus be administered simultaneously or in succession. The agent may furthermore alone or in combination be used together with a second active ingredient. These second active ingredients may be for the treatment of any of the herein mentioned diseases or disorders, or may be used for other purposes.

Another embodiment of the present invention comprises a kit of parts, wherein the kit includes at least one agent or pharmaceutical composition as described herein, a means for administering said vaccine and the instruction on how to do so. It is within the scope of the present invention to include multiple dosages of the same agent and/or pharmaceutical composition or several different agent and/or pharmaceutical compositions. In a preferred embodiment the kit of parts further comprises a second active ingredient.

Methods of Administration

Agents used in the methods of the present invention are generally administered to an animal in the form of a suitable pharmaceutical composition. Accordingly, the present invention also relates to a pharmaceutical composition comprising an agent as defined herein. Such compositions typically contain the agent and a pharmaceutically acceptable carrier. As used herein the language “pharmaceutically acceptable carrier” is intended to include any and all solvents, dispersion media, coatings, antibacterial and antifungal agents, isotonic and absorption delaying agents, and the like, compatible with pharmaceutical administration. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the agent, use thereof in the compositions is contemplated. Supplementary active compounds can also be incorporated into the compositions.

A pharmaceutical composition of the invention is formulated to be compatible with its intended route of administration. Examples of suitable routes of administration include parenteral, e.g., intravenous, intradermal, subcutaneous, oral (e.g., inhalation), transdermal (topical), transmucosal, and rectal administration. Solutions or suspensions used for parenteral, intradermal, or subcutaneous application can include the following components: a sterile diluent such as water for injection, saline solution, fixed oils, polyethylene glycols, glycerine, propylene glycol or other synthetic solvents; antibacterial agents such as benzyl alcohol or methyl parabens; antioxidants such as ascorbic acid or sodium bisulfite; chelating agents such as ethylenediaminetetraacetic acid; buffers such as acetates, citrates or phosphates and agents for the adjustment of tonicity such as sodium chloride or dextrose. The pH can be adjusted with acids or bases, such as hydrochloric acid or sodium hydroxide. The parenteral preparation can be enclosed in ampoules, disposable syringes or multiple dose vials made of glass or plastic.

Pharmaceutical compositions suitable for injectable use include sterile aqueous solutions (where water soluble) or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. For intravenous administration, suitable carriers include physiological saline, bacteriostatic water, Cremophor EL.TM. (BASF, Parsippany, N.J.) or phosphate buffered saline (PBS). In all cases, the composition must be sterile and should be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (for example, glycerol, propylene glycol, and liquid polyethylene glycol, and the like), and suitable mixtures thereof. The proper fluidity can be maintained, for example, by the use of a coating such as lecithin, by the maintenance of the required particle size in the case of dispersion and by the use of surfactants. Prevention of the action of microorganisms can be achieved by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, ascorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars, polyalcohols such as manitol, sorbitol, sodium chloride in the composition. Prolonged absorption of the injectable compositions can be brought about by including in the composition an agent which delays absorption, for example, aluminum monostearate and gelatin.

Sterile injectable solutions can be prepared by incorporating the agent in the required amount in an appropriate solvent with one or a combination of ingredients enumerated above, as required, followed by filtered sterilization. Generally, dispersions are prepared by incorporating the agent into a sterile vehicle which contains a basic dispersion medium and the required other ingredients from those enumerated above. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and freeze-drying which yields a powder of the active ingredient plus any additional desired ingredient from a previously sterile-filtered solution thereof.

Oral compositions generally include an inert diluent or an edible carrier. They can be enclosed in gelatine capsules or compressed into tablets. For the purpose of oral therapeutic administration, the agent can be incorporated with excipients and used in the form of tablets, troches, or capsules, oral compositions can also be prepared using a fluid carrier for use as a mouthwash, wherein the compound in the fluid carrier is applied orally and swished and expectorated or swallowed. Pharmaceutically compatible binding agents, and/or adjuvant materials can be included as part of the composition. The tablets, pills, capsules, troches and the like can contain any of the following ingredients, or compounds of a similar nature: a binder such as microcrystalline cellulose, gum tragacanth or gelatine; an excipient such as starch or lactose, a disintegrating agent such as alginic acid, Primogel, or corn starch; a lubricant such as magnesium stearate or Sterotes; a glidant such as colloidal silicon dioxide; a sweetening agent such as sucrose or saccharin; or a flavouring agent such as peppermint, methyl salicylate, or orange flavouring.

For administration by inhalation, the compounds are delivered in the form of an aerosol spray from pressured container or dispenser which contains a suitable propellant, e.g., a gas such as carbon dioxide, or a nebulizer.

Systemic administration can also be by transmucosal or transdermal means. For transmucosal or transdermal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art, and include, for example, for transmucosal administration, detergents, bile salts, and fusidic acid derivatives. Transmucosal administration can be accomplished through the use of nasal sprays or suppositories. For transdermal administration, the active compounds are formulated into ointments, salves, gels, or creams as generally known in the art.

The agent can also be prepared in the form of suppositories (e.g., with conventional suppository bases such as cocoa butter and other glycerides) or retention enemas for rectal delivery.

In one embodiment, the agent is prepared with carriers that will protect the compound against rapid elimination from the body, such as a controlled release formulation, including implants and microencapsulated delivery systems. Biodegradable, biocompatible polymers can be used, such as ethylene vinyl acetate, polyanhydrides, polyglycolic acid, collagen, polyorthoesters, and polylactic acid. Methods for preparation of such formulations will be apparent to those skilled in the art. The materials can also be obtained commercially from Alza Corporation and Nova Pharmaceuticals, Inc. Liposomal suspensions (including liposomes targeted to infected cells with monoclonal antibodies to viral antigens) can also be used as pharmaceutically acceptable carriers. These can be prepared according to methods known to those skilled in the art, for example, as described in U.S. Pat. No. 4,522,811.

It is especially advantageous to formulate oral or parenteral compositions in dosage unit form for ease of administration and uniformity of dosage. Dosage unit form as used herein refers to physically discrete units suited as unitary dosages for the subject to be treated; each unit containing a predetermined quantity of active compound calculated to produce the desired therapeutic effect in association with the required pharmaceutical carrier. The specification for the dosage unit forms of the invention are dictated by and directly dependent on the unique characteristics of the active compound and the particular therapeutic effect to be achieved, and the limitations inherent in the art of compounding such an active compound for the treatment of individuals.

Toxicity and therapeutic efficacy of such compounds can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., for determining the LD₅₀ (the dose lethal to 50% of the population) and the ED₅₀ (the dose. therapeutically effective in 50% of the population). The dose ratio between toxic and therapeutic effects is the therapeutic index and it can be expressed as the ratio LD₅₀/ED₅₀. Agents that exhibit large therapeutic indices are preferred. While agents that exhibit toxic side effects may be used, care should be taken to design a delivery system that targets such agents to the site of affected tissue in order to minimize potential damage to other cells and, thereby, reduce side effects.

The data obtained from the cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage of such compounds lies preferably within a range of circulating concentrations that include the ED₅₀ with little or no toxicity. The dosage may vary within this range depending upon the dosage form employed and the route of administration utilized. For any agent used in the method of the invention, the therapeutically effective dose can be estimated initially from cell culture assays. A dose may be formulated in animal models to achieve a circulating plasma concentration range that includes the IC_(0.50) (i.e., the concentration of the test agent which achieves a half-maximal inhibition of symptoms) as determined in cell culture. Such information can be used to more accurately determine useful doses in humans. Levels in plasma may be measured, for example, by high performance liquid chromatography. With respect to inhibition of Sortilin 10-20 μmol of Neurotensin is used to inhibit Sortilin in a cell culture.

The pharmaceutical compositions can be included in a container, pack, or dispenser together with instructions for administration.

The agents of the present invention can further be inserted into vectors and used in gene therapy. Gene therapy vectors can be delivered to a subject by, for example, intravenous injection, local administration (see U.S. Pat. No. 5,328,470) or by stereotactic injection (see e.g., Chen et al. (1994) Proc. Natl. Acad. Sci. USA 91:3054-3057). The pharmaceutical preparation of the gene therapy vector can include the gene therapy vector in an acceptable diluent, or can comprise a slow release matrix in which the gene delivery vehicle is imbedded. Alternatively, where the complete gene delivery vector can be produced intact from recombinant cells, e.g., retroviral vectors, the pharmaceutical preparation can include one or more cells which produce the gene delivery system.

Vectors suitable for use in gene therapy are known in the art. For example, adenovirus-derived vectors can be used. The genome of an adenovirus can be manipulated such that it encodes and expresses a gene product of interest but is inactivated in terms of its ability to replicate in a normal lytic viral life cycle. See for example Berkner et al. (1988) BioTechniques 6:616; Rosenfeld et al. (1991) Science 252:431-434; and Rosenfeld et al. (1992) Cell 68:143-155. Suitable adenoviral vectors derived from the adenovirus strain Ad type 5 dl324 or other strains of adenovirus (e.g., Ad2, Ad3, Ad7 etc.) are well known to those skilled in the art. Recombinant adenoviruses can be advantageous in certain circumstances in that they are not capable of infecting nondividing cells. Furthermore, the virus particle is relatively stable and amenable to purification and concentration, and as above, can be modified so as to affect the spectrum of infectivity. Additionally, introduced adenoviral DNA (and foreign DNA contained therein) is not integrated into the genome of a host cell but remains episomal, thereby avoiding potential problems that can occur as a result of insertional mutagenesis in situations where introduced DNA becomes integrated into the host genome (e.g., retroviral DNA). Moreover, the carrying capacity of the adenoviral genome for foreign DNA is large (up to 8 kilobases) relative to other gene delivery vectors (Berkner et al. cited supra; Haj-Ahmand and Graham (1986) J. Virol. 57:267). Most replication-defective adenoviral vectors currently in use and therefore favoured by the present invention are deleted for all or parts of the viral E1 and E3 genes but retain as much as 80% of the adenoviral genetic material (see, e.g., Jones et al. (1979) Cell 16:683; Berkner et al., supra; and Graham et al. in Methods in Molecular Biology, E. J. Murray, Ed. (Humana, Clifton, N. J., 1991) vol. 7, pp. 109-127). Expression of the gene of interest comprised in the nucleic acid molecule can be under control of, for example, the E1A promoter, the major late promoter (MLP) and associated leader sequences, the E3 promoter, or exogenously added promoter sequences.

Yet another viral vector system useful for delivery of the agents of the invention is the adeno-associated virus (AAV). Adeno-associated virus is a naturally occurring defective virus that requires another virus, such as an adenovirus or a herpes virus, as a helper virus for efficient replication and a productive life cycle. (For a review see Muzyczka et al. Curr. Topics in Micro. and Immunol. (1992) 158:97-129). Adeno-associated viruses exhibit a high frequency of stable integration (see for example Flotte et al. (1992) Am. J. Respir. Cell. Mot. Biol. 7:349-356; Samulski et al. (1989) J. Virol. 63:3822-3828; and McLaughlin et al. (1989) J. Virol. 62:1963-1973). Vectors containing as few as 300 base pairs of AAV can be packaged and can integrate. Space for exogenous DNA is limited to about 4.5 kb. An AAV vector such as that described in Tratschin et al. (1985) Mot. Cell. Biol. 5:3251-3260 can be used to introduce DNA into T cells. A variety of nucleic acids have been introduced into different cell types using AAV vectors (see for example Hermonat et al. (1984) Proc. Natl. Acad. Sci. USA 81:6466-6470; Tratschin et al. (1985) Mol. Cell. Biol. 4:2072-2081; Wondisford et al. (1988) Mol. Endocrinol. 2:32-39; Tratschin et al. (1984) J. Virol. 51:611-619; and Flotte et al. (1993) J. Biol. Chem. 268:3781-3790). Other viral vector systems that may be useful for delivery of the agents of the invention are derived from herpes virus, vaccinia virus, and several RNA viruses.

It should be understood that such treatments may also comprise administration of more than one agent, in which case the agents may be either administered concurrently and/or separately.

Animals

In one embodiment of the present invention, agents capable of inhibiting binding between a pro-neurotrophin and a Vps10p-domain receptor are administered to an animal. Said animal is preferably any animal that expresses a protein of the proneurotrophin family, more preferably a mammal, more preferably a domestic animal and most preferably a human being.

Methods for Screening for a Compound which Alters the Binding of at Least One Proneurotrophin to a Receptor of the Vps10p-Domain Receptor Family

In one preferred embodiment of the present invention, the invention comprises an in vitro method for screening for a compound which alters the binding of at least one pro-neurotrophin to a receptor of the Vps10p-domain receptor family, said method preferably comprising the steps of:

-   -   a) providing an assay for measuring the binding of a         pro-neurotrophin to the binding site of the receptor Sortilin         comprising SEQ ID NO. 25 or any variant or fragment thereof         (including SEQ ID NOs: 26 to 28,     -   b) adding the compound to be tested to the assay, and     -   c) determining the amount of a pro-neurotrophin bound to the         receptor of the Vps10p-domain receptor family, and     -   d) comparing the amount determined in step c) with an amount         measured in the absence of the compound to be tested,     -   e) wherein a difference in the two amounts identifies a compound         which alters the binding of pro-neurotrophins to the receptor of         the Vps10p-domain receptor family.

In one preferred embodiment of this screening method of the present invention, the pro-neurotrophin may be selected from pro-NGF, pro-BDNF, pro-NT-3 or pro-NT4/5. More preferably, the pro-neurotrophin is pro-NGF or pro-BDNF. In one preferred embodiment of this screening method, the receptor is selected from SorLA, Sortilin, SorCS1, SorCS3, or SorCS2. Even more preferably, the receptor is Sortilin. In another embodiment of the screening method of the present invention, the proneurotrophin is capable of binding to an extracellular part of the receptor. The receptor may in one embodiment of the present invention be a receptor that is expressed in a cell, within the plasma membrane and/or presented on a plasma membrane. The cell used in the screening method of the present invention may preferably be selected from primary cultures of neuronal cells, neurone-derived cell-lines, transfected cells capable of expressing receptor of the Vps10p-domain receptor family, peripheral neurons and central neurons. Preferably the cells are immortalised cell lines.

Assays that can be used for measuring the binding of a pro-neurotrophin to a receptor of the Vps10p-domain receptor family are well-known to those skilled in the art and include, but are not restricted to, yeast two-hybrid assays, competitive binding methods, such as RIAs, ELISAs, and the like. Other tests are Fluorescence resonance energy transfer (FRET), Surface plasmon resonance (Biacore), Western blotting, immunohistochemistry. Results from binding studies can be analyzed using any conventional graphical representation of the binding data, such as Scatchard analysis (Scatchard, Ann. NY Acad. Sci., 51:660-672 [1949]; Goodwin et al., Cell, 73:447-456 [1993]), and the like.

In another embodiment of the present invention, a method is provided for determining the effect of an agent on activity of pro-neurotrophins in cells presenting a receptor of the Vps10p-domain receptor family. Said method comprises the steps of:

-   -   b) administering said agent to a mammal expressing the receptor,     -   c) measuring the activity of pro-neurotrophins in said mammal,     -   d) comparing the measurement of step b) with a measurement         obtained in the absence of the compound to be tested,     -   e) wherein the difference in the two measurements identifies the         effect of said agent on the activity of proneurotrophins on         cells presenting receptors of the Vps10p-domain receptor family.

The mammal may express the receptor naturally or may be transfected with the wild-type receptor gene.

The activity of said pro-neurotrophins in said mammal may be measured by one or more of the following measurements:

-   -   a) measuring expression level of proneurotrophin responsive         target gene, such as mRNA or protein in tissues of the mammal,     -   b) measuring expression level of a receptor as defined herein,         such as mRNA or protein in tissues of the mammal     -   c) measuring receptor-mediated binding or transport of         pro-neurotrophins bound to the receptor,     -   d) measuring uptake of pro-neurotrophins into cells of said         mammal,     -   e) measuring signal transduction from said receptor or a related         receptor in cells of said mammal,

The related receptor may be p75 receptor or TrkA receptor.

In a preferred embodiment of said method, the method further comprises administering said agent to a mammal lacking expression of said receptor. Said mammal lacking expression of said receptor may only lack expression of said receptor in one or more selected tissues, and/or may have a lowered expression level of said receptor.

Methods for measuring expression of receptor mRNA or protein in tissues of the mammal are well known to those skilled in the art and have been described earlier. Methods for measuring receptor-mediated binding or transport of neurotrophins and/or pro-neurotrophins bound to the receptor are also well-known to those skilled in the art: said methods include, but are not restricted to, yeast two-hybrid screening, Biacore RTM screening, UV cross-linking, and immunoprecipitation.

Methods for measuring the uptake of pro-neurotrophins into cells of a mammal are also well known to those skilled in the art: said methods include but are not restricted to a method wherein proneurotrophin uptake is measured in cells presenting the receptor and cells not representing the receptor. The proneurotrophin is preferably labelled, such as labelled radioactively or fluorescently.

In another embodiment of the present invention, a method is provided for modulating the transport of at least one neurotrophin and/or pro-neurotrophin out of, or into a cell line or neuron of an animal, said method comprising administering to said animal a sufficient amount of an agent capable of binding a receptor of the Vps10p-domain receptor family. Said modulation may comprise an increase in the anterograde transport of the neurotrophin and/or pro-neurotrophin in the neuron. The modulation may alternatively comprise a decrease in anterograde transport of the neurotrophin and/or pro-neurotrophin in the neuron. In another preferred embodiment, the modulation comprises an increase in the retrograde transport of the neurotrophin and/or pro-neurotrophin in the neuron. In another preferred embodiment, the modulation comprises an decrease in retrograde transport of the pro-neurotrophin in the neuron. The modulation may be conducted by an agent as discussed above.

Library of Agents

In the present invention, libraries of compounds may be used to screen for agents capable of inhibiting binding between a Vps10p-domain receptor and a pro-neurotrophin.

As used herein, the term “library” means a collection of molecular entities or test compounds according to the present invention, herein also designated “library members”.

In preferred embodiments of the present invention the library is a combinatorial library. Non-limiting examples of combinatorial libraries that may be used with the present invention and methods of producing such libraries are given in: Comprehensive Survey of Combinatorial Library Synthesis: 1998 Roland E. Dolle and Kingsley H. Nelson, Jr. J. Comb. Chem., 1999, pp 235-282; Comprehensive Survey of Combinatorial Library Synthesis: 1999 Roland E. Dolle J. Comb. Chem., 2000, pp 383-433; Comprehensive Survey of Combinatorial Library Synthesis: 2000 Roland E. Dolle J. Comb. Chem., 2001, pp 477-517; Comprehensive Survey of Combinatorial Library Synthesis: 2001 Roland E. Dolle J. Comb. Chem., 2002, pp 369-418 and Comprehensive Survey of Combinatorial Library Synthesis: 2002 Roland E. Dolle J. Comb. Chem., 2003, pp 693-753. The skilled person will appreciate that these protocols may be easily adapted to specific need of a particular embodiment of the present invention.

In one embodiment, these molecular entities can be natural oligomers (oligomers of building blocks occurring in nature) such as peptides, glycopeptides, lipopeptides, nucleic acids (DNA or RNA), or oligosaccharides. By way of example, a natural oligomer may be any peptide consisting of naturally occurring amino acid, even if said peptide comprises a sequence not present in nature. The libraries may comprise different natural oligomers or the libraries may comprise only one kind of natural oligomer, for example the library may be a peptide library. In another embodiment, they can be unnatural oligomers (oligomers comprising one or more building blocks not occurring in nature) such as chemically modified peptides, glycopeptides, nucleic acids (DNA or RNA), or, oligosaccharides, and the like. Said chemical modification may for example be the use of unnatural building blocks connected by the natural bond linking the units (for example, a peptide amide linkage), the use of natural building blocks with modified linking units (for example, oligoureas as discussed in Boeijen et al, 2001, J. Org. Chem., 66: 8454-8462; oligosulfonamides as discussed in Monnee et al, 2000, Tetrahedron Lett., 41: 7991-95), or combinations of these (for example, statine amides as discussed in Dolle et al, 2000, J. Comb. Chem., 2: 716-31.). Preferred unnatural oligomers include oligomers comprising unnatural building blocks connected to each other by a naturally occurring bond linking. Said oligomers may thus comprise a mixture of naturally occurring and unnatural building blockslinked to each other by naturally occurring bonds. By way of example, the oligomer may comprise naturally occurring amino acids and unnatural building blocks linked by peptide bonds f.x. PNA or LNA. Thus, in one embodiment of the invention preferred oligomers comprise modified amino acids or amino acid mimics). Other preferred unnatural oligomers include, for example oligoureas, poly azatides, aromatic C—C linked oligomers and aromatic C—N linked oligomers. Still other preferred oligomers comprise a mixture of natural and unnatural building blocks and natural and unnatural linking bonds. For example, the unnatural oligomer may be any of the oligomers mentioned in recent reviews see: Graven et al., 2001, J. Comb. Chem., 3: 441-52; St. Hilaire et al., 2000, Angew. Chem. Int. Ed. Engl., 39: 1162-79; James, 2001, Curr. Opin. Pharmacol., 1: 540-6; Marcaurelle et al., 2002, Curr. Opin. Chem. Biol., 6: 289-96; Breinbauer et al., 2002, Angew. Chem. Int. Ed. Engl., 41: 2879-90. The libraries of the invention may also comprise cyclic oligomers, for example cyclic natural oligomers, such as cyclic peptides or cyclic unnatural oligomers. In certain embodiments of the invention, libraries of cyclic oligomers may be advantageous to use due to the rigid structure. This may result in higher selectively and affinity.

In yet another embodiment, the molecular entities may comprise non-oligomeric molecules such as peptidomimetics or other small organic molecules. Peptidomimetics are compounds that mimic the action of a peptidic messenger, such as bicyclic thiazolidine lactam peptidomimetics of L-proplyl-L-leucylglycinamide (Khalil et al, 1999, J. Med. Chem., 42: 2977-87). In a preferred embodiment of the invention, the library comprises or even more preferably consists of small organic molecules. Small organic molecules are non-oligomeric compounds of less than about 600 mass units containing any of a variety of possible functional groups and are the product of chemical synthesis, or isolated from nature, or isolated from nature and then chemically modified, and include, for example, Bayer's urea-based kinase inhibitors (Smith et at, 2001, Bioorg. Med. Chem. Lett, 11: 2775-78). Small organic compounds may for example be selected from the group consisting of alcohols, ethers, carboxylic acids, aryloxy, acyloxy, thiol, alkylthio, arylthio, heteroarylthio, sulphonyi, sulphoxy, amino, alkylamino, dialkylamino, acylamino, diacylamino, alkoxycarbonylamino, amides, alkyl, branched alkyl, aryl, heteroaryl, nitro, cyano, halogeno, silyloxy, keto, heterocycles, fused ring systems, fused heterocycles and mixtures thereof, wherein each of the aforementioned may be substituted independently on each position with one or more groups selected from the group consisting of —H, —SH, halogen, carboxyl, carbonyl, alkoxy, aryloxy, acyloxy, alkylthio, arylthio, heteroarylthio, sulphonyl, sulphoxy, amino, alkylamino, dialkylamino, acylamino, diacylamino, alkoxycarbonylamino, amides, alkyl, aryl, heteroaryl, nitro, cyano, halogeno, silyloxy, keto, heterocycles, fused ring systems, and fused heterocycles.

Non-limiting examples of small organic molecule libraries that may be used with the present invention and methods of producing them may for example be found in the reviews Thompson et at, 1996, Chem. Rev., 96: 555-600; Al-Obeidi et at, 1998, Mol. Biotechnol., 9: 205-23; Nefzi et al., 2001, Biopolymers, 60: 212-9; Dolle, 2002, J. Comb. Chem., 4: 369-418.

The libraries according to the invention may comprise at least 20, such as at least 100, for example at least 1000, such as at least 10,000, for example at least 100,000, such as at least 1,000,000 different test compounds. Preferably, the libraries comprises in the range of 20 to 10⁷, more preferably 50 to 7,000,000, even more preferably 100 to 5,000,000, yet more preferably 250 to 2,000,000 different compounds. In a very preferred embodiment of the present invention the libraries comprises in the range of 1000 to 20,000, such as in the range of 20,000 to 200,000 different test compounds. In preferred embodiments of the invention the library comprises in the range of 10,000 to 1,000,000 different test compounds.

Selection of an appropriate library is dependent upon the specific embodiment of the invention. For example, a totally random library designed to contain greatly diverse compounds may be used for screening for agents of the present invention. An advantage of this approach is that the outcome of the screening is not prejudiced in any specific manner.

Alternatively, a smaller, targeted library (hundreds to thousands of compounds) can be used, for example, starting with a known compound or compounds, and providing numerous variations of these known compounds for targeted screening. Alternatively, a smaller targeted library of compounds mimicking a compound known to inhibit binding between a pro-neurotrophin and a Vps-10pdomain receptor such as a Sortilin receptor may be prepared, for example using computer aided modelling followed by chemical synthesis. The smaller, targeted library can also comprise random molecules.

In one aspect the present invention also relates to methods of synthesizing libraries of test compounds, wherein said libraries are in particular useful for the screening for agents capable of inhibiting binding between a pro-neurotrophin and a Sortilin receptor especially SEQ ID NO: 25 of said Sortilin receptor or any fragment or variant of said SEQ ID NO. 25, said fragment having at least 70% sequence identity to SEQ ID NO. 25.

The libraries may be used by the general screening method described in example 5. By utilising a pipetting robot the method allows screening of very large libraries for the identification of agents capable of inhibiting binding between pro-neurotrophins and Sortilin. The agents may be any agent according to the present invention.

DESCRIPTION OF DRAWINGS

FIG. 1: Examples of Vps10p-domain receptors. Their structural composition is indicated.

FIG. 2: Characterization of NGF binding to p75, TrkA, and Sortilin as measured by surface plasmon resonance analysis (BIAcore). Binding of 50-500 nM NGF was measured to 91.5 fmol/mm² immobilized p75-IgG-Fc chimeric protein (upper panel), to 66 fmol/mm² immobilized TrkA-IgG-Fc (middle panel), and to 51 fmol/mm² purified Sortilin extracellular domain (lower panel). The on and off rates—100 to 600 seconds and 600 to 1000 seconds, respectively—were recorded and the Kd values for NGF binding were calculated to ˜1 nM for p75, ˜2 nM for TrkA, and ˜8 nM for Sortilin. Mature murine NGF was from Austral Biologicals (San Ramon, Calif.), recombinant human p75 neurotrophin receptor/Fc and human TrkA/Fc chimeras were from R&D systems (Oxon, UK). Human Sortilin was produced in stably transfected CHOcells and purified as described elsewhere (Munck Petersen et al, EMBO J. (1999) 18:595-604).

All the data provided in this figure were obtained by surface plasmon resonance measurements (Biacore analysis).

FIG. 3: Characterization of proNGF binding to p75, TrkA, and Sortilin as measured by surface plasmon resonance analysis (Biacore). Binding of 25-500 nM proNGF was measured to 91.5 fmol/mm² immobilized p75-IgG-Fc chimeric protein (upper panel), to 66 fmol/mm² immobilized TrkA-IgG-Fc (middle panel), and to 51 fmol/mm² purified Sortilin extracellular domain (lower panel). The on and off rates—100 to 600 seconds and 600 to 1000 seconds, respectively—were recorded and the Kd values for proNGF binding were calculated to ˜12 nM for p75, ˜15 nM for TrkA, and ˜5 nM for Sortilin. Human recombinant proNGF was produced and purified in E. coli as described (Rattenholl et al, Eur. J. Biochem. (2001) 268:3296-3303). All other reagents were as described in the legend to FIG. 2. All the data provided in this figure were obtained by surface plasmon resonance measurements (Biacore analysis)

FIG. 4: Characterization of binding of the proNGF propeptide to p75, TrkA, and Sortilin as measured by surface plasmon resonance analysis (Biacore). Binding of 25-500 nM propeptide was measured to 91.5 fmol/mm² immobilized p75-19G-Fc chimeric protein (upper panel), to 66 fmol/mm² immobilized TrkA-IgG-Fc (middle panel), and to 51 fmol/mm² purified Sortilin extracellular domain (lower panel). The on and off rates—100 to 600 seconds and 600 to 1000 seconds, respectively—were recorded and the Kd values for proNGF propeptide binding were calculated to ˜8 nM for Sortilin. There was no detectable binding to p75 and TrkA. The human NGF-propeptide expressed in E. Coli was provided by Elisabeth Schwarz, Martin-Luther-Universität Halle-Wittenberg, Halle/Saale, Germany. All other reagents were as described in the legends to FIGS. 2 and 3. All the data provided in this figure were obtained by surface plasmon resonance measurements (Biacore analysis)

FIG. 5: This reference example which is not a part of the present invention demonstrates that it is possible to inhibit binding of a pro-neurotrophin to a Vps10p-domain receptor. The reference example figure displays inhibition of proNGF binding to immobilized Sortilin by neurotensin as measured by Biacore analysis. Binding of 200 nM proNGF to 51 fmol/mm² immobilized Sortilin is inhibited by ˜45% following coinjection with 10 WO neurotensin. Binding of neurotensin alone is shown for comparison. Neurotensin was obtained from Sigma-Aldrich (St. Louis, Mo.). All other products were as indicated above. All the data provided in this figure were obtained by surface plasmon resonance measurements (Biacore analysis)

FIG. 6: This reference example which is not a part of the present invention demonstrates that it is possible to inhibit binding of a pro-neurotrophin to a Vps10p-domain receptor. The reference example figure displays proNGF binding to immobilized Sortilin by RAP (receptor-associated protein), the propeptide of proNGF, and the Sortilin propeptide. The inhibitors were prebound to Sortilin followed by coinjection with 200 nM proNGF. The baselines have been corrected for the signals obtained in the presence of each of the inhibitors. Maximal proNGF binding is measured without preincubation with the respective inhibitors. Binding of 200 nM proNGF to 51 fmol/mm² immobilized Sortilin is inhibited ˜65% by 10 μM RAP, ˜85% by 5 μM og the proNGF propeptide and ˜65% by 5 μM the Sortilin propeptide. All the data provided in this figure were obtained by surface plasmon resonance measurements (Biacore analysis)

FIG. 7: Characterization of binding of BDNF and the pro-domain of proBDNF to purified Sortilin as measured by surface plasmon resonance (Biacore). Mature recombinant human BDNF was from Promega (#G1491) and the pro-domain of human BDNF fused to GST (glutathione S-transferase) was produced in E. coli and purified by glutathione-sepharose affinity chromatography. Binding of the pro-domain of proBDNF (a GST-fusion protein, upper panel) or BDNF (lower panel) was measured to 94 fmol/mm2 immobilized purified Sortilin extracellular domain. The experiment was carried out essentially as described for FIGS. 2-4. The on and off rates—100 to 600 seconds and 600 to 10000 seconds, respectively—were recorded and the Kd values for ligand binding were calculated to ˜58 nM for the GST-pro-domain of proBDNF, and ˜40 nM for mature BDNF. Other preparations of mature BDNF have shown Kd values for ligand binding at 10 nM. All the data provided in this figure were obtained by surface plasmon resonance measurements (Biacore analysis)

FIG. 8: Functional characterization of recombinant his-S-tagged neurotrophin pro-domains. A. Coomassie staining of purified polypeptides of pro-dom-NGF (residues Glu¹-Arg¹⁰²) and pro-dom-BDNF (residues Ala¹-Arg¹¹⁰) cloned into the pET-30 fXa/LIC vector (Novagen) that adds the two N-terminal poly-histidine and S-peptide tags. B, C. The presence of both tags is verified by Western blotting and detection by using a primary antibody against histidine followed by incubation with HRP-conjugated secondary antibody (B) or with a directly HRP-conjugated version of S-protein (C). D, E. Surface plasmon resonance analysis of the binding of the bacterial pro-domains of NGF (D) and BDNF (E) to the immobilized extracellular domain of sortilin.

FIG. 9: Alignment of the amino acid sequences of the four mammalian neurotrophins. An alignment of the sequences of NGF, BOW, NT-3, and NT-4/5, showing a high degree of conservation for the mature part, and much less sequence conservation among the pro-domains. Strictly conserved residues are highlighted on a black background, and partly conserved residues on a grey background.

FIG. 10: SPOT analysis of pro-dom-NGF/BDNF binding to Vps10p receptors including sortilin and detection with HRP-S-protein. Membranes containing overlapping 16-mer peptides of the five human Vps10p-domain containing receptors (Sortilin, SorLA, SorCS1, SorCS2, and SorCS3) were incubated either in the presence of pro-dom-NGF (20 μg/mL, A) or pro-dom-BDNF (20 μg/mL, B) or in the absence of ligand (C). Bound ligand was detected by incubation of the membrane with HRP-conjugated S-protein, that also binds specifically to control peptides present on the upper left and lower right corner of each dissected receptor. A specific binding site for the neurotrophin pro-domains is shown in the box consisting of three consecutive sortilin binding peptides (SPOTs 67-68-69), but is not seen for detection solely using the HAP-S-protein.

FIG. 11: SPOT analysis of pro-dom-BDNF binding to sortilin using the anti-histidine immunodetection. Repeated analysis of pro-dom-BDNF binding to the peptide library but detection using a primary antibody against poly-histidine followed by a HRP-conjugated anti-mouse secondary antibody showed a slight shift towards a specific interaction with peptides 64-65-66 (B), which is not identified when the membrane was not incubated with ligand prior to detection (A). SPOTs corresponding to 22-25 represent binding of the detection system independent on pro-domBDNF.

FIG. 12: Independent confirmation of pro-dom-BDNF binding to SPOTs 67-68-69 15 by HAP-S-protein detection. A new membrane was synthesized and probed for a newly produced batch of pro-dom-BDNF showing specific binding to SPOTs 67-68-69 at 1 min of exposure (A) to verify the binding to reside around this sortilin sequence. Following 5 min of exposure, a few additional peptides also show minor interactions.

FIG. 13: Amino acid sequence of SPOTs 64-69. The 16-mer sortilin sequences that correspond to SPOTs 64-69 likely to harbor the major binding site for pro-domains of neurotrophins.

FIG. 14: Alignment of the sortilin Vps10p domain. The repeated presence of the Asp-box motif (S/T-X-D-X-G-X-X-W/F) was used to make an alignment displaying an internal sequence repetition found in e.g. domains having a beta-propeller fold, where residues located around this motif are present on the molecular surface. Strictly conserved residues are highlighted on a black background, and partly conserved residues on a grey background.

FIG. 15: Substitution analysis of the RIFRSSDFAKNFVQTD peptide (SEQ ID NO:25, residues 7-22). Pro-dom-BDNF binding analysis to a peptide with the wild-type sortilin sequence RIFRSSDFAKNFVQTD (SEQ ID NO:25, residues 7-22) listed to the left on the membrane. Binding to mutant peptides where each amino acid has been substituted with each of the 20 naturally occurring amino acids is used for identification of specific residues important for interaction with the immature part of neurotrophins. Detection using either HRP-S-protein (A) or the anti-histidine immunospecific method (B) identifies virtually identical residues for this method. C, D. Bar graph representation of the binding variation upon amino acid substitution. This method might be suitable for identification of super-binding peptides.

FIG. 16: Substitution analysis of pro-dom-BDNF binding to RIFRSSDF (SEQ ID NO:1, residues 7-14) and FAKNFVQTD (SEQ ID NO:1, residues 14-22) peptides. A, B. Splitting of the peptide shown in FIG. 8 provides evidence that the longer peptide contains two independent binding motifs for prodom-BDNF binding. The substitution analysis clearly identify the two sequences RIFR (A) (SEQ ID NO:1, residues 7-10) and FAKNF (B) (SEQ ID NO:1, residues 14-18) as specific interaction sites for the pro-domains of BDNF. C. Confirmation by substitution analysis that the FAKNF (SEQ ID NO:1, residues 14-18) motif is not C-terminal extended.

FIG. 17: Length analysis of pro-dom-BDNF binding to sortilin peptides. By deletion of single amino acid residues, the length of a minimal functional sortilin peptide is determined, confirming that small e.g. tetrameric sequences have high affinity for pro-dom-BDNF (highlighted in white on black background).

FIG. 18: Surface plasmon resonance binding analysis of sortilin peptides to pro-dom-NGF and -BDNF. The direct interaction between sortilin peptides (as identified by SPOT analysis) and the pro-domains of NGF and BDNF was verified by surface plasmon resonance analysis using immobilized pro-dom-NGF and -BDNF. A concentration series of the RSSDFAKNFVQTDLPF peptide (A) (SEQ ID NO:25, residues 10-25) (containing only one of the two potential binding sites residing in this region) or the RIFRSSDFAKNF (B) (SEQ ID NO:25, residues 7-18) confirming the result of a direct binding as seen from the immobilized peptide analysis on the SPOT membrane. By comparison of binding curves (sensorgrams) for a single peptide concentration to flow cells containing identical amounts of immobilized pro-dom-NGF and -BDNF, a higher affinity of the peptides towards BDNF than NGF could be observed, in line with previous reports describing a similar pattern for the binding of pro-BDNF and pro-NGF to full-length sortilin, supporting the concept that these peptides contain a major binding epitope. The numbering in this figure refers to the mature part of Sortilin.

FIG. 19: Surface plasmon resonance analysis of competition studies by the sortilin peptides. Recombinant sortilin was purified from 293 cells, and used for binding studies to immobilized pro-dom-BDNF (-peptide; RSSDFAKNFVQTDLPF) (SEQ ID NO:25, residues 10-25), and binding was significantly inhibited in the presence of the identified sortilin peptides (+peptide). The inset indicates a similar effect of the peptide in the competition of sortilin binding to immobilized pro-dom-NGF, and the quality of applied sortilin is indicated to the right by a silver stained SDS-PAGE analysis.

FIG. 20: Thermal hypoalgesia in Sortilin deficient mice as determined by the hot plate assay. The hot plate test was performed as follows. Wild-type (sortilin+/+) and sortilin knockout mice (sortilin−/−) were placed on a thermoregulated Plactronic hot plate set at 55° C. Each animal was subsequently observed for licking their hind-limb or jumping in response to the heat. The first response was registered per animal. A 30 sec cut-off was employed in order to prevent tissue damage.

FIG. 21: Representative sensorgrams of pro-dom-NGF binding at similar concentration series of 10, 20, 30, 40, and 50 nM to biosensor chips containing immobilized sortilin wt or single residue mutations as indicated. Each sortilin construct was immobilized to a similar surface density allowing for direct comparison among different receptor domains.

FIG. 22: Surface plasmon resonance analysis of 50 nM GST-pro-dom-NGF binding to immobilized sortilin wt or the sortilin quatro mutant (containing quadruple substitution at R163A, F165A, R166A, F170A) as indicated. Binding is severely affected upon mutation deleting the entire RIFR (SEQ ID NO:25, residues 7-10) motif and the proximal phenylalanine residue of the FAKNF (SEQ ID NO:25, residues 14-18) motif as seen by the much lower response level.

EXAMPLES Example 1 Materials and Proteins

To obtain tagged forms of the neurotrophin pro-domains readily for detection in SPOT analysis, constructs were prepared for each protein allowing for addition of N-terminal S-peptide and poly-histidine tags. Template cDNA for human NGF and BDNF was ATCC clones used for generation of fragments spanning residues Glu1-Arg102 of NGF (SEQ ID NO:6) and Ala1-Arg110 of BDNF (SEQ ID NO:7) using the primer pairs 5′GGTATTGAGGGTCGCGAACCACACTCAGAGAGCAATGTCCC3′ (SEQ ID NO:45), 3′GGGGGAAGTTGTCCTGAGTGTCCTCGTTCGCCACTCCGAGATTGAGAGGAGA5′ (SEQ ID NO:46) and 5′GGTATTGAGGGTCGCGCCCCCATGAAAGAAGCAAACATCCGAGG3′ (SEQ ID NO:47), 3′CACGTTTGTACAGGTACTCCCAGGCCGCGACTCCGAGATTGAGAGGAGA5′ (SEQ ID NO:48), with compatible overhangs for ligation independent cloning into the pET-30 Xa/LIC vector from Novagen (cat. no. 70073-3) and amplification using Phusion DNA polymerase and following the protocol as provided by manufacturer. Proteins were expressed in the BL21/DE3 strain of E. coli, efficiently extracted from bacterial inclusion bodies using the Bugbuster reagent from Novagen (cat. no. 70921) with added benzonase (Novagen, cat. no. 70750), and purified by standard Ni2+−NTA affinity chromatography in 500 mM NaCl, 5 mM Imidazole, and 20 mM TrisHCl, pH 8.0. Protein elution was performed in buffer supplemented with 20 mM EDTA. Verification of the intact tagged versions of pro-domain-NGF and pro-domain-BDNF was carried out by SDS-PAGE analysis followed by commassie staining or Western blotting using either antibody against the histidine tag from Sigma (H-1029) and secondary HRP-conjugated anti-mouse antibody from Calbiochem (cat. no. 401207), or alternatively by direct binding of HRP-conjugated S-protein from Novagen (cat. no. 69047-3).

For the production of the Sortilin ectodomain, a construct encompassing the entire coding region of the N-terminal part of human Sortilin including the endogenous signal peptide and followed by a C-terminal poly-histidine tag inserted in the pCEP-Pu vector was kindly provided by D. Militz, Berlin. The DNA was transferred into EBNA293 cells that were selected by G418 (Gibco cat. no. 10131-027, 300 ug/ml) and Puromycin from Sigma (cat. no. P8833, 1 ug/ml) before proteins were collected from medium conditioned for 48 h, and used for purification by applying to Ni2+−NTA Sepharose. The secreted recombinant Sortilin polypeptide chain spanning the entire 35 extracellular domain of human Sortilin is thus ending at Ser725 (+AMIEGRGVGHHHHHH containing the fXa site and poly-histidine tag (SEQ ID NO:61)). The quality of the protein was tested by silver staining of SDS-PAGE analysis. Peptides for binding and competition studies were synthesized in house, or from Eurogentec.

Example 2 Surface Plasmon Resonance Analysis

Determination of direct binding of ligand to immobilized protein was performed on a Biacore2000 instrument (Biacore, Sweden) using CaHBS as standard running buffer (10 mM HEPES, pH 7.4, 140 mM NaCl, 2 mM CaCl₂, 1 mM EGTA, and 0.005% Tween-20). A biosensor chip from Biacore (CM5, cat. no. BR-1000-14) was activated using the NHS/EDC method as described by supplier followed by coating with Sortilin to a protein density of 79 fmol/mm2, and used for affinity measurements of the recombinant pro-domains of NGF and BDNF. Regeneration of the flow cell after each cycle of ligand binding experiment was performed by two 10 ul pulses of regeneration buffer (10 mM glycine-HCl, pH 4.0, 500 mM NaCl, 20 mM EDTA, and 0.005% Tween-20) and a single injection of 0.001% SDS. Fitting of sensorgrams for affinity estimations was performed using the Biaevaluation version 3.1.

Following similar protocols, immobilization of pro-dom-NGF or pro-dom-BDNF was also performed on a CM5 biosensor chip using the NHS/EDC coupling kit according to manufacturer's instructions (Biacore, Sweden), giving similar surface densities of immobilized protein (−300 fmol/mm2). Purified peptides were applied to the chip at increasing concentrations to verify the direct binding of pro-neurotrophic domains to linear Sortilin peptides. This chip was subsequently used to examine the binding of 390 nM wild-type Sortilin domain in CaHBS buffer at a flow of 5 uL/min, which in the absence of any competing peptide gave a ˜300 RU signal. For competition using 300 uM of the peptide, only ⅓ of the Sortilin can bind to immobilized pro-dom-BDNF (showing ˜66% inhibition by the peptide).

Example 3 Cellulose Membrane Preparation

Peptide libraries were generated for all members of the Vps10p-domain receptor gene family or specific peptide variations in terms of substitution or length of identified Sortilin binding peptides. A total of 2181 peptides was used for representation of the Sortilin gene family, corresponding to 273 peptides for Sortilin (accession code:CAA66904), 734 peptides for SorLA (accession code: NP_(—)003096), 389 peptides for SorCS1 (accession code: NP_(—)001 013049), 382 peptides for sorCS2 (accession code: Q96PQ0), and 403 peptides for SorCS3 (accession code: CA164579), with a 13 amino acid overlap between 16-mers.

A cellulose support is prepared as a N-modified cellulose-amino-hydroxylpropyl ether membrane, and all rounds of synthesis starts with SPOT definition by 9-fluorenyl-methoxycarbonyl-β-alanine-pentafluoophenyl ester that creates an alanine linker between peptide and membrane. Then followed an automated linear synthesis of stepwise addition of the different amino acids protected at their amino terminal by 9-fluorenyl-methoxycarbonyl and appropriate side chain protection for the growing peptide chain. The pattern of deprotection, activation, and coupling continued until 16-mer peptides were produced, resulting in an equally distributed array of covalently anchored peptides to the cellulose support at their C-terminal and an N-terminal free end. The membrane was finally blocked in blocking buffer from Sigma (cat. no. B6429) diluted in TBS and supplemented with 5% saccharose (Merck, cat. no. K32055087 422) for 2 h before the predefined peptide library is ready for ligand binding analysis.

Example 4 Binding Studies of Cellulose-Bound Peptides

The membrane-bound libraries were incubated with a combined S-peptide and poly-histidine-tagged pro-domains (10 ug/mL) in blocking buffer over night at 4 C, followed by a second incubation with 1 ug/mL of HRP-conjugated S-protein from Novagen (cat. no. 69047-3) also in blocking buffer but for 3 h at room temperature. Subsequently, the membrane was washed three times for 10 min with TBS before quantitative characterization of bound ligand was carried out using the UptiLight chemoluminescence substrate from Uptima (cat. no. UP99619A) and the LumiImager instrument from Roche Diagnostics, providing the SPOT signal intensities in Boehringer Light Units (BLUs). Alternatively, detection of bound ligand was performed by an immunochemical assay, where antibody against the histidine tag was from Sigma (H-1029) and the secondary HRP-conjugated anti-mouse antibody was from Calbiochem (cat. no. 401207). Incubations followed standard Western blotting procedures and SPOT detection as above.

The method of substitution analysis and length analysis to identify unique single amino acid residues and to determine the minimal peptide sequence, respectively, for efficient binding of the pro-domain-neurothrophins to the Sortilin peptide, followed similar protocols as for the initial testing of ligand binding to the SPOT membrane.

Example 5 Radioligand Assay

Recombinant Sortilin (38 pmol) is labeled with [¹²⁵I] using the lodogen iodination reagent from Pierce (cat. no. 28600) to a specific activity of ˜5×10¹⁸ cpm/mol Sortilin. The pro-dom-NGF (or -BDNF) is coated in maxisorp microtiter wells from Nunc (cat. no. 439454) by incubation for 16 h at 4 C in 50 mM NaHCO₃, pH 9.6. After blocking using 5% bovine serum albumin (Sigma, cat. no. A9647) for 2 h at room temperature, the wells are washed three times with MB buffer (10 mM HEPES, pH 7.4, 140 mM NaCl, 2 mM CaCl₂, and 1 mM MgCl₂) before incubation with ¹²⁵I-Sortilin allowing for total binding of ˜2.000 cpm/well and varying amounts of competing peptide concentrations are performed for 16 h at 4° C. in MB buffer supplemented with 2% bovine serum albumin. Following washes with MB buffer, bound radioactivity is released by adding 10% SDS. Nonspecific binding of tracer to wells coated only with bovine serum albumin is determined and subtracted from the values determined in the binding experiments. Fitting data point to binding equations using the Prism software from GraphPad, version 4, made estimation of IC₅₀ constants.

Example 6 Investigation of Antagonistic Properties

Investigation of the properties of the peptide as an in vivo antagonist of proneurotrophin binding to Sortilin in an animal model of nerve lesions in the rat brain.

i) Determination of IC₅₀ values for the full-length peptide as well as smaller peptides as identified from our recent length analysis illustrate that the 4-mer peptides (e.g. RIFR) binds very strongly to the pro-domains of pro-NGF and pro-BDNF. This will be performed either by: i-a)¹²⁵I-labelling of Sortilin and solid state competition assays using immobilized pro-domain-NGF/BDNF in maxisorb microtiter wells, followed by competition studies using increasing levels of the various peptides in order to compare inhibitory properties. i-b) Using surface plasmon resonance analysis for concentration series of the various peptides similar to the results displayed for a single concentration of A2 peptide. ii) Testing the influence of essential residues as identified by the substitution analysis for their contribution to pro-neurotrophin binding. Using the EBNA293 expression system for recombinant production of the Sortilin ectodomain (silver stained gel was included in one of the figures), single-residues alanine mutants of the Sortilin domain are currently produced using site-directed mutagenesis. The following 7 mutants have been tested: R160A, R163A, F165A, R166A, F170A, K172A, F174A as numbered according to pro-Sortilin specified in the sequence overview. Due to the indicated presence of two binding sites within this Sortilin region, production of double, triple, etc. mutants for verification of the binding site in the context of the entire Sortilin Vps10p domain might be required. iii) Provided that it is possible to identify residues from (ii), essential for the interaction between Sortilin and the pro-domain of pro-NGF/BDNF, preparation of expression vectors (in pcDNA3.1/invitrogen) for the full-length Sortilin protein carrying such mutations will be performed. Use of these constructs (together with p75^(NTR)) for cell transfection should produce cells insensitive to pro-NGF mediated cell death as compared to wild-type Sortilin, since this pathway is disrupted. iv) Application of the peptides (or derivatives of these) to the cell culture system for neuronal cell death, to verify that the peptides work as functional inhibitors. v) Provided that identification of successful inhibitors can be performed, they could be utilized for rescue experiments in nerve lesions experiments for the rat brain.

Example 7 Binding Studies of Site Directed Mutants

Site-directed mutagenesis was performed for all important residues within the peptide sequence as identified by the substitution analysis in the SPOT method, using the pCepPU expression vector for sortilin as template. The thereby generated mutant constructs were used together with HEK293 cells to produce single residue mutants of the his-tagged sortilin luminal domain, to obtain the proteins R163A, F165A, R166A, F170A, K172A, and F174A numbered according to pro-Sortilin as specified in the sequence overview. As a control protein, the mutant R160A located N-terminally to the recognition sequence, was produced in order to have a protein with unaltered affinity for the NGF-prodomain.

After purification by standard Ni²⁺-NTA chromatography, each sortilin mutant was immobilized to a similar surface density on Biacore CM5 chips. Binding was tested using concentration series of the previously described GST-NGF-pro-domain fusion protein (Nykjr et al., Nature 2004), which is able to render a higher response using the SPR system at low concentration. Thus concentration series of 10, 20, 30, 40, and 50 nM GST-prodomain of NGF was applied to each chip surface, and data was fitted to a 1:1 binding model using the standard BIAevaluation software. Representative sensorgrams are presented in FIG. 21, and the binding parameters provided in Table 1 below.

TABLE 1 R¹⁶³1FRSSDFAKNF¹⁷⁴ (SEQ ID NO: 25, Residues 7-18) Kinetic parameters for the binding reaction of GST-pro-dom-NGF (tested at 10-50 nM concentrations) to sortilin mutants as presented in FIG. 21. Binding curves were fitted using the BIAevaluation 3.1 software, showing that all produced single residue mutants exhibit a similar affinity towards the pro-neurotrophin domain as does the non-mutated receptor, although the F170A and F174A variants binds with a lower capacity as seen from the lower read out on the curves in FIG. 21. The numbering is according to pro-Sortilin as specified in the sequence overview. Site-directed PCR- SEQ ID 10 nM-50 nM series of sensograms mutants clones NO ka kd KD wt RGGRIARSSDFAKNF 25 (Residues 4-18) R160A AGGRIFRSSDFAKNF 50 1.47 × 10⁵ 2.27 × 10⁻⁴ 1.89 nM R163A RGGAIFRSSDFAKNF 51 1.85 × 10⁵ 4.21 × 10⁻⁴ 2.70 nM F165A RGGRIARSSDFAKNF 52 1.10 × 10⁵ 4.22 × 10⁻⁴ 3.86 nM R166A RGGRIFASSDFAKNF 53 6.48 × 10⁴ 2.85 × 10⁻⁴ 4.38 nM F170A RGGRIFRSSDAAKNF 54 1.30 × 10⁵ 5.91 × 10⁻⁴  5.59 nM* K172A RGGRIARSSDFAANF 55 1.01 × 10⁵ 3.46 × 10⁻⁴ 3.91 nM F174A RGGRIFRSSDFAKNA 56 2.35 × 10⁵ 1.03 × 10⁻³  4.27 nM* quatro RGGAIAASSDAAKNF 57 no binding *these two mutants exhibit reduced binding capacity -- but similar affinity.

As described in the length analysis experiments, the peptide seem to carry two independent binding motives, one made by the RIFR (SEQ ID NO:25, residues 7-10) and one by FAKNF (SEQ ID NO:25, residues 14-18), as the small peptides RIFRSSDF (SEQ ID NO:25, residues 7-14:) and FAKNFVQTD (SEQ ID NO:25, residues 14-22) displayed efficient binding of the prodomain-NGF and pro-domain-BDNF in the SPOT analysis. This model is further supported by the previous data in the substitution analysis, where a stronger effect upon mutation was observed when using peptides containing only one of the binding motives, as compared to mutants spanning both motives. Accordingly, it was decided to “remove” an entire motif before substitution within the second motif and to be able to observe how that would influence binding of the ligand. A sortilin variant was produced containing quadruple substitutions (R163A, F165A, R166A, and 15 F170A) in a similar procedure using HEK293 cells as applied for single residue mutants. It was noticed that this protein was secreted into the medium of the HEK293 cells demonstrating that the quatro mutant was still able to fold into a soluble protein

To determine ligand binding capacity, quatro protein was coupled in parallel to the wild-type sortilin on a new Biacore chip, and binding of GST-pro-NGF was measured in a manner similar to the analysis of single residue mutants (FIG. 21). A strongly reduced affinity for pro-neurotrophin domain binding was found, supporting the conclusion that a major binding site for the ligands is contained in the RGGRIFRSSDFAKNF peptide (SEQ ID NO:25, residues 4-18).

Binding of other ligands such as neurotensin and sortilin's own pro-peptide may be tested in a manner analogous to what is described herein above.

Example 8 Identification of Pro-Neurotrophin Binding Sites on the Sortilin Receptor

To identify antagonists for the neurotrophin pro-domain binding site in sortilin (i.e. the RGGRIFRSSDFAKNF peptide (SEQ ID NO:25, residues 4-18), the following set of experiments are performed:

Labeling of pro-NGF and the pro-dom-NGF is performed using the IODOGEN method and ¹²⁵I from Amersham Biosciences. HEK293 cells are transfected with the sortilin expression vector using the HIFECT transfection reagent to optimize the efficience. 24 hours post-transfection, cells are incubated at 4° C. for 2 hours before applying radio-ligand for 16 hours at 4° C. in 10 mM HEPES, pH 7.4, 150 mM NaCl, 2 mM CaCl₂, and 1 mM MgCl₂ both in the absence and in the presence of candidate antagonists. Binding of ligand to sortilin is determined as cell-associated radioactivity. In a similar experiment conducted at 37° C., we will measure the amount of degraded ligand as counts secreted into the cell media over a time period of 16 hours. The ability of candidate antagonists to protect against pro-NGF induced apoptosis, is conducted as described (Jansen et al., Nature Neurosci., 2007).

The purification of the his-tagged sortilin extracellular domain is performed as described elsewhere, and coupled to the Nickel chelate (His-Tag) PS SPA Imaging scintillation beads according to the protocol of the manufacturer (GE Healthcare Life Sciences).

Single well homogenous assay is used for the direct quantitation of candidate agonist-induced or inverse induced ¹²⁵I-pro-NGF or ¹²⁵I-pro-dom-NGF binding activity for receptors coupled to the scintillation beads is performed by following guidelines as provided by GE Healthcare Life Sciences.

The antagonistic properties are tested in competition experiments using a scintillation proximity assay in a reverse setup. Prodomain of NGF fused to GST (described in Nykjcer, Nature, 2007) is coupled to Glutathione immobilized scintillation beads (GE Healthcare Life Sciences) and inhibition is determined using a radio-labeled 125I-RGGRIFRSSDFAKNF (SEQ ID NO:25, residues 4-18) or 125I-labeled intact sortilin extracellular domain binding to the beads by candidate antagonists as described above.

Antagonists binding directly to the RGGRIFRSSDFAKNF (SEQ ID NO:25, residues 4-18) motif (as such molecules are very likely to interfere with the interaction of the particular ligand to intact sortilin) are identified. The peptide is synthesized by Eurogentec, Liege, Belgium, and immobilized to a CM5 biacore sensor chip (cat. no. BR-1000-14) using the NHS/EDC coupling kit (Biacore, Sweden). Binding properties of the candidate molecules are evaluated by screening their binding to the receptor/peptide at various concentrations in 10 mM HEPES, pH 7.4, 150 mM NaCl, 2 mM CaCl₂, 0.005% Tween-20 as running buffer.

Overview of Sequences SEQ ID NO 1: Sortilin SEQ ID NO 2: SorLA SEQ ID NO 3: SorCS1 SEQ ID NO 4: SorCS2 SEQ ID NO 5: SorCS3

SEQ ID NO 6: pre-pro-NGF SEQ ID NO 7: pre-pro-BDNF

SEQ ID NO 8: Neurotrophin-3 SEQ ID NO 9: Neurotrophin-4/5 SEQ ID NO 10: Neurotensin (1-13) SEQ ID NO 11: Neuromedin

SEQ ID NO 12: Receptor associated peptide (RAP) SEQ ID NO 13: pro-Neurotensin/pro-Neuromedin

SEQ ID NO 14: NT(8-13) SEQ ID NO 15: NT66L SEQ ID NO 16: NT67L SEQ ID NO 17: NT69L SEQ ID NO 18: Eisai SEQ ID NO 19: JMV-449 SEQ ID NO 20: PD-149163 SEQ ID NO 21: PD-149598 SEQ ID NO 22: PD-156425 SEQ ID NO 23: PD-156556 SEQ ID NO 24: CGX-1160 SEQ ID NO 25: Mature Sortilin G113-M143

-   -   pro-Sortilin G157-M187     -   pre-pro-Sortilin G190-M220

SEQ ID NO 26: Mature Sortilin R196-F207

-   -   pro-Sortilin G163-M187     -   pre-pro-Sortilin G196-M220

SEQ ID NO 27: Mature Sortilin G119-M122

-   -   pro-Sortilin G163-M166     -   pre-pro-Sortilin G196-M199

SEQ ID NO 28: Mature Sortilin G126-M130

-   -   pro-Sortilin G 170-M 17 4     -   pre-pro-Sortilin G203-M207

SEQ ID NO 29: PD-47113 SEQ ID NO 30: GZR-123 SEQ ID NO. 31: NT64D SEQ ID NO. 32: NT64L SEQ ID NO. 33: NT65L SEQ ID NO. 34: NT66D SEQ ID NO. 35: NT69L′ SEQ ID NO. 36: NT71 SEQ ID NO. 37: NT72 SEQ ID NO. 38: NT73 SEQ ID NO. 39: NT74 SEQ ID NO. 40: NT75 SEQ ID NO. 41: NT76 SEQ ID NO. 42: NT77

SEQ ID NO. 43: Signal peptide of Sortilin SEQ ID NO. 44: SorCS2 peptide

SEQ ID NO. 45: Primer SEQ ID NO. 46: Primer SEQ ID NO. 47: Primer SEQ ID NO. 48: Primer

SEQ ID NO. 49: Peptide containing fXa site and poly-histidine tag SEQ ID NO. 50: R160A Site-Directed PCR clone SEQ ID NO. 51: R163A Site-Directed PCR clone SEQ ID NO. 52: F165A Site-Directed PCR clone SEQ ID NO. 53: R166A Site-Directed PCR clone SEQ ID NO. 54: F170A Site-Directed PCR clone SEQ ID NO. 55: K172A Site-Directed PCR clone SEQ ID NO. 56: F174A Site-Directed PCR clone SEQ ID NO. 57: Quatro Site-Directed PCR clone 

What is claimed is:
 1. An in vitro screening method for selecting a compound which alters the binding of at least one pro-neurotrophin to a binding site on Sortilin, comprising: (a) providing an assay for measuring the binding of a pro-neurotrophin to a binding site on Sortilin, wherein said binding site comprises SEQ ID N0:25 or variant or fragment thereof; (b) adding the compound to be tested to the assay; (c) determining the amount of a pro-neurotrophin bound to the binding site on Sortilin; (d) comparing the amount determined in step c) with an amount determined in the absence of the compound to be tested; and (e) selecting a compound having a difference in the two amounts as a compound which alters the binding of pro-neurotrophins to the Sortilin.
 2. The method of claim 1, wherein the pro-neurotrophin is selected from proNGF of SEQ ID NO:6, pro-BDNF of SEQ ID NO:7, pro-NT-3 of SEQ ID NO:8 or proNT-4/5 of SEQ ID NO:9.
 3. The method of claim 1, wherein said binding site on Sortilin receptor comprises SEQ ID NO:25, SEQ ID NO:26, SEQ ID NO:27, or SEQ ID NO:28.
 4. A method for determining the degree of inhibition of an agent on the activity of pro-neurotrophins in cells expressing a receptor selected from the Vps10p-domain receptors of SEQ ID NOs: 1 to 5 or any fragment of variant thereof, said variant having at least 70% sequence identity to any of said SEQ ID NOs: 1 to 5, said method comprising the steps of: (a) administering said agent to a mammal expressing said receptor, (b) measuring the activity of said pro-neurotrophins in said mammal; and (c) determining the degree of inhibition by comparing the measurement of step (b) with a measurement obtained in the absence of said agent being tested, wherein the difference in the two measurements identifies the degree of inhibition of said agent on the activity of pro-neurotrophins on cells expressing said receptor.
 5. A pharmaceutical composition comprising: (a) (1) an agent capable of binding any of SEQ ID NOs. 25 to 28 or a variant or fragment thereof; or (2) an agent comprising any of SEQ ID NOs. 25 to 28 or a variant or fragment thereof capable of binding a proneurotrophin selected from the group consisting of proNGF, proBDNF, proNT3 and proNT4/5; or (3) an antibody capable of binding to any of SEQ ID NOs: 25 to 28; and (b) a pharmaceutically acceptable carrier.
 6. A kit in parts comprising: (a) a composition of claim 5; (b) a medical instrument or other means for administering the composition; and (c) instructions on how to use the kit in parts.
 7. The kit of claim 6, further comprising a second active ingredient. 